docs(readme): add project summary, features, and tech highlights

Expand the README intro with a stronger project summary (incl. GLM-5.2/OpenCode origin, ~4M input / ~800K output tokens, ~$82), a Features list, and a Tech Highlights section (SSE, custom migration system, Playwright E2E, Vitest, etc.). Existing content continues below.

README.md

@@ -1,9 +1,48 @@
 # OpenGroupware
 
-A simple, self-contained, project-based groupware built with **Next.js 15**, **TypeScript**, and
-**SQLite**. It runs entirely on Node.js (no external database or storage) and provides boards,
-Markdown notes, realtime chat (SSE), a Kanban ToDo board, file sharing, a calendar with milestones,
-meetings with schedule-conflict detection, search, dashboards, and admin backups.
+![OpenGroupware demo](docs/screenshots/demo.gif)
+
+OpenGroupware is a full-featured, self-contained, project-based groupware built with **Next.js 15**,
+**TypeScript**, and **SQLite**. It runs entirely on Node.js — no external database, cache, or object
+storage — and packs boards, realtime chat, a Kanban ToDo board, Markdown notes, file sharing, a
+calendar with milestones, meetings with schedule-conflict detection, search, dashboards,
+notifications, and admin backups into a single deployable app.
+
+> **Origin:** This project was built as a test of **GLM-5.2** with **OpenCode**. The vast majority of
+> the codebase was generated autonomously, without human interaction. Total usage: ~4M input tokens,
+> ~800K output tokens, ~**$82** in API cost.
+
+## Features
+
+- **Project workspaces** — multi-project, with member roles (admin / member / guest) and permission-checked access throughout
+- **Boards** — threaded discussions with Markdown, categories, pinning, important flags, and file/image attachments
+- **Realtime chat** — per-project SSE live messages with @mentions and attachments (auto-reconnect via `EventSource`)
+- **Kanban ToDo board** — drag-and-drop columns & cards, priorities, assignees, start/due dates, tags, milestones, and attachments
+- **Markdown notes** — pinned notes, tags, full search, and sanitized rendering
+- **File sharing** — uploads with a lightbox, library + attachment sources, and project-scoped storage
+- **Calendar** — month/week/day views with events linked to todos, milestones, and meetings
+- **Milestones** — due dates, status, and progress roll-up across todos
+- **Meetings** — agenda & minutes (Markdown), invited members, and schedule-conflict detection
+- **Search & dashboards** — cross-project search and a personal dashboard
+- **Notifications & activity log** — mentions, assignments, due-soon, and meeting invites, plus a per-project audit trail
+- **Admin tools** — one-click backup (SQLite DB + uploads → ZIP), download, and migration status (system_admin only)
+- **Auth** — bcrypt password hashing, stateless signed-cookie sessions, and system_admin / member roles
+- **PWA & mobile** — installable, responsive, with an offline shell
+- **Theme & i18n** — dark/light theme and English / Japanese UI
+
+## Tech Highlights
+
+- **Strict layered architecture** — `UI (app/) → Service (services/) → Repository (repositories/) → Data (lib/db/)`; one-way dependencies, SQL isolated in repositories
+- **Realtime via SSE** — a tiny in-memory `SseHub` (`lib/sse/hub.ts`) broadcasts events to per-project clients; services inject the hub and fire events on writes
+- **Custom SQL migration system** — `Migrator` (`lib/db/migrator.ts`) applies versioned `lib/db/migrations/NNN_*.sql` files in filename order, each in its own transaction and recorded in `schema_migrations` — no ORM, no external CLI
+- **SQLite wrapper** — `SqliteDatabase` centralizes `better-sqlite3` access with WAL mode, `foreign_keys = ON`, parameter binding, and transactions; repositories never touch the driver directly
+- **Stateless signed sessions** — `base64url(payload).base64url(hmacSha256(secret, payload))` cookies verified with `crypto.timingSafeEqual` and an `iat` expiry
+- **Playwright E2E tests** — `webServer` auto-runs `migrate && dev`, a `globalSetup` seeds the admin account, `workers: 1` for deterministic SSE; 15 specs cover every major user flow
+- **Vitest unit & integration tests** — 326 tests across 38 files using a real temporary SQLite DB per test, with an 80% coverage threshold on repositories and services
+- **Soft deletes everywhere** — `deleted_at IS NULL` filtering enforced in repository queries
+- **XSS-safe Markdown** — `react-markdown` + `remark-gfm` + `rehype-sanitize`; HTML and dangerous URL schemes are stripped
+- **Key algorithms, unit-tested** — schedule-conflict detection, milestone progress calculation, notification targeting, and session-token verification
+- **Spec-driven workflow** — opencode-driven design docs (`docs/`) and per-task steering files (`.steering/`) keep planning and implementation traceable
 
 The codebase follows a strict **layered architecture**:
 

app/api/projects/[projectId]/todos/items/[itemId]/route.ts

@@ -6,6 +6,23 @@ import { handleApiError, jsonError } from '@/lib/api/handleError';
 
 export const runtime = 'nodejs';
 
+export async function GET(
+  _request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; itemId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { itemId } = await params;
+  const service = createTodoService();
+  try {
+    const item = service.getItem(user.id, Number(itemId));
+    const attachments = service.getItemAttachments(user.id, Number(itemId));
+    return NextResponse.json({ item, attachments });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}
+
 export async function PATCH(
   request: NextRequest,
   { params }: { params: Promise<{ projectId: string; itemId: string }> }
@@ -35,23 +52,29 @@ export async function PATCH(
       );
       return NextResponse.json({ item });
     }
+    // nullable フィールドは absent(undefined=更新しない) と null(クリア) を区別する
+    const nullableString = (v: unknown): string | null | undefined =>
+      v === undefined ? undefined : v === null ? null : String(v);
+    const nullableNumber = (v: unknown): number | null | undefined =>
+      v === undefined ? undefined : v === null ? null : Number(v);
+
     const item = service.updateItem(user.id, Number(itemId), {
       title: typeof body.title === 'string' ? body.title : undefined,
-      description:
-        typeof body.description === 'string' ? body.description : undefined,
-      assigneeId:
-        body.assigneeId === null || body.assigneeId === undefined
-          ? undefined
-          : Number(body.assigneeId),
+      description: nullableString(body.description),
+      assigneeId: nullableNumber(body.assigneeId),
       priority:
         typeof body.priority === 'string'
           ? (body.priority as 'low' | 'normal' | 'high')
           : undefined,
-      dueDate: typeof body.dueDate === 'string' ? body.dueDate : undefined,
-      milestoneId:
-        body.milestoneId === null || body.milestoneId === undefined
-          ? undefined
-          : Number(body.milestoneId),
+      startDate: nullableString(body.startDate),
+      dueDate: nullableString(body.dueDate),
+      tags: nullableString(body.tags),
+      milestoneId: nullableNumber(body.milestoneId),
+      fileIds: Array.isArray(body.fileIds)
+        ? body.fileIds
+            .map((n) => Number(n))
+            .filter((n) => Number.isFinite(n) && n > 0)
+        : undefined,
     });
     return NextResponse.json({ item });
   } catch (error) {

app/api/projects/[projectId]/todos/items/reorder/route.ts

@@ -0,0 +1,46 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { createTodoService } from '@/lib/api/services';
+import { UnauthorizedError } from '@/lib/errors';
+import { handleApiError, jsonError } from '@/lib/api/handleError';
+
+export const runtime = 'nodejs';
+
+/**
+ * カラム内のアイテム順序を一括再採番する(同一カラムの並べ替え / 他カラムからの移動)。
+ * body: { columnId: number, itemIds: number[] } —— itemIds の順序で orderIndex 0..n-1 を割り当てる。
+ */
+export async function POST(
+  request: NextRequest,
+  { params }: { params: Promise<{ projectId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { projectId } = await params;
+  let body: Record<string, unknown>;
+  try {
+    body = (await request.json()) as Record<string, unknown>;
+  } catch {
+    return jsonError(400, 'リクエスト本文が不正です');
+  }
+
+  const columnId = Number(body.columnId);
+  const itemIds = Array.isArray(body.itemIds)
+    ? body.itemIds
+        .map((n) => Number(n))
+        .filter((n) => Number.isFinite(n) && n > 0)
+    : [];
+
+  const service = createTodoService();
+  try {
+    const items = service.reorderItems(
+      user.id,
+      Number(projectId),
+      columnId,
+      itemIds
+    );
+    return NextResponse.json({ items });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}

app/api/projects/[projectId]/todos/items/route.ts

@@ -38,6 +38,11 @@ export async function POST(
   }
   const service = createTodoService();
   try {
+    const fileIds = Array.isArray(body.fileIds)
+      ? body.fileIds
+          .map((n) => Number(n))
+          .filter((n) => Number.isFinite(n) && n > 0)
+      : [];
     const item = service.createItem(user.id, Number(projectId), {
       title: String(body.title ?? ''),
       columnId: Number(body.columnId ?? 0),
@@ -51,7 +56,11 @@ export async function POST(
         typeof body.priority === 'string'
           ? (body.priority as 'low' | 'normal' | 'high')
           : undefined,
+      startDate:
+        typeof body.startDate === 'string' ? body.startDate : undefined,
       dueDate: typeof body.dueDate === 'string' ? body.dueDate : null,
+      tags: typeof body.tags === 'string' ? body.tags : undefined,
+      fileIds,
     });
     return NextResponse.json({ item }, { status: 201 });
   } catch (error) {

app/api/users/me/route.ts

@@ -5,6 +5,8 @@ import { getDb } from '@/lib/db/sqlite';
 import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
 import { UnauthorizedError } from '@/lib/errors';
 import { handleApiError, jsonError } from '@/lib/api/handleError';
+import type { Locale, Theme } from '@/lib/types';
+import { PREF_MAX_AGE } from '@/lib/i18n/constants';
 
 export const runtime = 'nodejs';
 
@@ -21,6 +23,7 @@ export async function PATCH(request: NextRequest) {
     return jsonError(400, 'リクエスト本文が不正です');
   }
 
+  // theme/locale は生値を Service に渡し、バリデータで不正値を弾く(→ ValidationError → 400)
   const authService = new AuthService(new UserRepository(getDb()));
   try {
     const updated = authService.updateProfile(currentUser.id, {
@@ -28,8 +31,23 @@ export async function PATCH(request: NextRequest) {
       email: typeof body.email === 'string' ? body.email : undefined,
       avatarUrl:
         typeof body.avatarUrl === 'string' ? body.avatarUrl : undefined,
+      theme: typeof body.theme === 'string' ? (body.theme as Theme) : undefined,
+      locale:
+        typeof body.locale === 'string' ? (body.locale as Locale) : undefined,
     });
-    return NextResponse.json({ user: toPublicUser(updated) });
+    const res = NextResponse.json({ user: toPublicUser(updated) });
+    // 保存結果の theme/locale をCookieに反映(SSRでレイアウトが読めるように)
+    res.cookies.set('theme', updated.theme, {
+      path: '/',
+      maxAge: PREF_MAX_AGE,
+      sameSite: 'lax',
+    });
+    res.cookies.set('locale', updated.locale, {
+      path: '/',
+      maxAge: PREF_MAX_AGE,
+      sameSite: 'lax',
+    });
+    return res;
   } catch (error) {
     return handleApiError(error);
   }

app/dashboard/page.tsx

@@ -4,6 +4,7 @@ import { createDashboardService } from '@/lib/api/services';
 import { Header } from '@/components/layout/Header';
 import { CreateProjectForm } from '@/components/project/CreateProjectForm';
 import { DashboardWidget } from '@/components/project/DashboardWidget';
+import { getLocale, translate } from '@/lib/i18n/server';
 
 export const dynamic = 'force-dynamic';
 
@@ -15,20 +16,26 @@ export default async function DashboardPage() {
 
   const service = createDashboardService();
   const dashboard = service.getPersonalDashboard(user.id);
+  const locale = await getLocale();
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <main className="mx-auto max-w-4xl space-y-6 p-6">
-        <h1 className="text-2xl font-bold">ダッシュボード</h1>
+        <h1 className="text-2xl font-bold">
+          {translate('page.dashboard', locale)}
+        </h1>
 
         <div className="grid gap-4 sm:grid-cols-2">
-          <DashboardWidget title="参加プロジェクト" empty="ありません">
+          <DashboardWidget
+            title={translate('dash.projects', locale)}
+            empty={translate('dash.empty', locale)}
+          >
             {dashboard.projects.map((p) => (
               <a
                 key={p.id}
                 href={`/projects/${p.id}`}
-                className="block rounded border px-3 py-2 text-sm hover:bg-gray-50"
+                className="block rounded border px-3 py-2 text-sm hover:bg-gray-50 dark:border-gray-700 dark:hover:bg-gray-800"
               >
                 {p.name}（{p.status}）
               </a>
@@ -36,35 +43,46 @@ export default async function DashboardPage() {
           </DashboardWidget>
 
           <DashboardWidget
-            title={`未読通知 (${dashboard.unreadNotificationCount})`}
-            empty="未読はありません"
+            title={`${translate('dash.unreadNotifications', locale)} (${dashboard.unreadNotificationCount})`}
+            empty={translate('dash.noUnread', locale)}
           >
             <a
               href="/notifications"
-              className="text-sm text-blue-600 hover:underline"
+              className="text-sm text-blue-600 hover:underline dark:text-blue-400"
             >
-              通知一覧を開く
+              {translate('dash.openNotifications', locale)}
             </a>
           </DashboardWidget>
 
-          <DashboardWidget title="未完了ToDo" empty="ありません">
+          <DashboardWidget
+            title={translate('dash.incompleteTodos', locale)}
+            empty={translate('dash.empty', locale)}
+          >
             {dashboard.incompleteTodos.map((t) => (
               <p key={t.id} className="text-sm">
                 {t.title}
-                {t.dueDate ? `（期限: ${t.dueDate}）` : ''}
+                {t.dueDate
+                  ? `（${translate('dash.due', locale)}: ${t.dueDate}）`
+                  : ''}
               </p>
             ))}
           </DashboardWidget>
 
-          <DashboardWidget title="期限切れタスク" empty="ありません">
+          <DashboardWidget
+            title={translate('dash.overdueTasks', locale)}
+            empty={translate('dash.empty', locale)}
+          >
             {dashboard.overdueTasks.map((t) => (
               <p key={t.id} className="text-sm text-red-600">
-                {t.title}（期限: {t.dueDate}）
+                {t.title}（{translate('dash.due', locale)}: {t.dueDate}）
               </p>
             ))}
           </DashboardWidget>
 
-          <DashboardWidget title="近日中のミーティング" empty="ありません">
+          <DashboardWidget
+            title={translate('dash.upcomingMeetings', locale)}
+            empty={translate('dash.empty', locale)}
+          >
             {dashboard.upcomingMeetings.map((m) => (
               <p key={m.id} className="text-sm">
                 {m.title}（{m.startAt}）
@@ -72,7 +90,10 @@ export default async function DashboardPage() {
             ))}
           </DashboardWidget>
 
-          <DashboardWidget title="最近のアクティビティ" empty="ありません">
+          <DashboardWidget
+            title={translate('dash.recentActivity', locale)}
+            empty={translate('dash.empty', locale)}
+          >
             {dashboard.recentActivity.map((l) => (
               <p key={l.id} className="text-sm">
                 {l.action}（{l.targetType}）

app/globals.css

@@ -1,3 +1,12 @@
 @tailwind base;
 @tailwind components;
 @tailwind utilities;
+
+/* ルート要素の最低限のダーク/ライト背景フォールバック。
+   各コンポーネントは dark: ユーティリティで個別に調整している。 */
+html {
+  color-scheme: light dark;
+}
+body {
+  @apply bg-gray-50 text-gray-800 dark:bg-gray-900 dark:text-gray-100;
+}

app/layout.tsx

@@ -1,20 +1,61 @@
-import type { Metadata } from 'next';
+import type { Metadata, Viewport } from 'next';
+import { cookies } from 'next/headers';
 import './globals.css';
+import { I18nProvider } from '@/lib/i18n/I18nProvider';
+import { ServiceWorkerRegister } from '@/components/pwa/ServiceWorkerRegister';
+import type { Locale, Theme } from '@/lib/types';
 
 export const metadata: Metadata = {
-  title: 'シンプルグループウェア',
-  description:
-    'プロジェクト単位で情報共有・タスク管理を行えるチームコラボレーションツール',
+  title: 'Groupware',
+  description: 'Project-based team collaboration tool',
+  applicationName: 'Groupware',
+  appleWebApp: {
+    capable: true,
+    statusBarStyle: 'default',
+    title: 'Groupware',
+  },
+  icons: {
+    icon: '/icon.svg',
+    apple: '/icon-192.png',
+  },
 };
 
-export default function RootLayout({
+export const viewport: Viewport = {
+  width: 'device-width',
+  initialScale: 1,
+  viewportFit: 'cover',
+  themeColor: '#2563eb',
+};
+
+function resolveTheme(v: string | undefined): Theme {
+  return v === 'light' ? 'light' : 'dark'; // 既定は dark
+}
+
+function resolveLocale(v: string | undefined): Locale {
+  return v === 'ja' ? 'ja' : 'en'; // 既定は en
+}
+
+export default async function RootLayout({
   children,
 }: {
   children: React.ReactNode;
 }) {
+  const cookieStore = await cookies();
+  const theme = resolveTheme(cookieStore.get('theme')?.value);
+  const locale = resolveLocale(cookieStore.get('locale')?.value);
+
   return (
-    <html lang="ja">
-      <body>{children}</body>
+    <html
+      lang={locale}
+      className={theme === 'dark' ? 'dark' : ''}
+      style={{ colorScheme: theme }}
+    >
+      <body>
+        <I18nProvider initialLocale={locale} initialTheme={theme}>
+          {children}
+        </I18nProvider>
+        <ServiceWorkerRegister />
+      </body>
     </html>
   );
 }

app/login/page.tsx

@@ -2,11 +2,13 @@
 
 import { useState, type FormEvent } from 'react';
 import { useRouter } from 'next/navigation';
+import { useI18n } from '@/lib/i18n/I18nProvider';
 
 type Mode = 'login' | 'register';
 
 export default function LoginPage() {
   const router = useRouter();
+  const { t } = useI18n();
   const [mode, setMode] = useState<Mode>('login');
   const [name, setName] = useState('');
   const [email, setEmail] = useState('');
@@ -38,22 +40,22 @@ export default function LoginPage() {
     const data = (await res.json().catch(() => null)) as {
       error?: { message?: string };
     } | null;
-    setError(data?.error?.message ?? '処理に失敗しました');
+    setError(data?.error?.message ?? t('auth.failed'));
     setLoading(false);
   }
 
   return (
-    <main className="flex min-h-screen flex-col items-center justify-center bg-gray-50 p-8">
-      <div className="w-full max-w-sm rounded-lg border bg-white p-8 shadow-sm">
+    <main className="flex min-h-screen flex-col items-center justify-center bg-gray-50 p-8 dark:bg-gray-900">
+      <div className="w-full max-w-sm rounded-lg border bg-white p-8 shadow-sm dark:border-gray-700 dark:bg-gray-800">
         <h1 className="text-2xl font-bold">
-          {mode === 'login' ? 'ログイン' : '新規登録'}
+          {mode === 'login' ? t('auth.login') : t('auth.register')}
         </h1>
 
         <form className="mt-6 space-y-4" onSubmit={onSubmit}>
           {mode === 'register' && (
             <div>
               <label htmlFor="name" className="block text-sm font-medium">
-                表示名
+                {t('auth.displayName')}
               </label>
               <input
                 id="name"
@@ -61,14 +63,14 @@ export default function LoginPage() {
                 type="text"
                 value={name}
                 onChange={(e) => setName(e.target.value)}
-                className="mt-1 w-full rounded border px-3 py-2"
+                className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
                 required
               />
             </div>
           )}
           <div>
             <label htmlFor="email" className="block text-sm font-medium">
-              メールアドレス
+              {t('auth.email')}
             </label>
             <input
               id="email"
@@ -77,13 +79,13 @@ export default function LoginPage() {
               autoComplete="email"
               value={email}
               onChange={(e) => setEmail(e.target.value)}
-              className="mt-1 w-full rounded border px-3 py-2"
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
               required
             />
           </div>
           <div>
             <label htmlFor="password" className="block text-sm font-medium">
-              パスワード
+              {t('auth.password')}
             </label>
             <input
               id="password"
@@ -94,7 +96,7 @@ export default function LoginPage() {
               }
               value={password}
               onChange={(e) => setPassword(e.target.value)}
-              className="mt-1 w-full rounded border px-3 py-2"
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
               required
               minLength={8}
             />
@@ -111,19 +113,23 @@ export default function LoginPage() {
             disabled={loading}
             className="w-full rounded bg-blue-600 px-4 py-2 font-medium text-white hover:bg-blue-700 disabled:opacity-50"
           >
-            {loading ? '処理中...' : mode === 'login' ? 'ログイン' : '登録する'}
+            {loading
+              ? t('auth.processing')
+              : mode === 'login'
+                ? t('auth.loginButton')
+                : t('auth.registerButton')}
           </button>
         </form>
 
         <button
           type="button"
-          className="mt-4 w-full text-center text-sm text-blue-600 hover:underline"
+          className="mt-4 w-full text-center text-sm text-blue-600 hover:underline dark:text-blue-400"
           onClick={() => {
             setMode(mode === 'login' ? 'register' : 'login');
             setError(null);
           }}
         >
-          {mode === 'login' ? '新規登録はこちら' : 'ログイン画面に戻る'}
+          {mode === 'login' ? t('auth.registerHere') : t('auth.backToLogin')}
         </button>
       </div>
     </main>

app/manifest.ts

@@ -0,0 +1,51 @@
+import type { MetadataRoute } from 'next';
+
+/**
+ * PWA マニフェスト。Next.js が /manifest.webmanifest を生成し、
+ * <link rel="manifest"> を自動で <head> に出力する。
+ */
+export default function manifest(): MetadataRoute.Manifest {
+  return {
+    name: 'Groupware',
+    short_name: 'Groupware',
+    description: 'Project-based team collaboration tool',
+    start_url: '/',
+    scope: '/',
+    display: 'standalone',
+    orientation: 'any',
+    background_color: '#111827',
+    theme_color: '#2563eb',
+    lang: 'en',
+    icons: [
+      {
+        src: '/icon-192.png',
+        sizes: '192x192',
+        type: 'image/png',
+        purpose: 'any',
+      },
+      {
+        src: '/icon-192.png',
+        sizes: '192x192',
+        type: 'image/png',
+        purpose: 'maskable',
+      },
+      {
+        src: '/icon-512.png',
+        sizes: '512x512',
+        type: 'image/png',
+        purpose: 'any',
+      },
+      {
+        src: '/icon-512.png',
+        sizes: '512x512',
+        type: 'image/png',
+        purpose: 'maskable',
+      },
+      {
+        src: '/icon.svg',
+        sizes: 'any',
+        type: 'image/svg+xml',
+      },
+    ],
+  };
+}

app/notifications/page.tsx

@@ -16,7 +16,7 @@ export default async function NotificationsPage() {
   const { items } = service.listUnread(user.id, 1);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <main className="mx-auto max-w-2xl space-y-6 p-6">
         <h1 className="text-2xl font-bold">通知</h1>

app/profile/page.tsx

@@ -3,9 +3,11 @@
 import { useEffect, useState, type FormEvent } from 'react';
 import { useRouter } from 'next/navigation';
 import type { PublicUser } from '@/lib/auth/getCurrentUser';
+import { useI18n } from '@/lib/i18n/I18nProvider';
 
 export default function ProfilePage() {
   const router = useRouter();
+  const { t, locale, theme, setLocale, setTheme } = useI18n();
   const [user, setUser] = useState<PublicUser | null>(null);
   const [loading, setLoading] = useState(true);
   const [name, setName] = useState('');
@@ -44,7 +46,7 @@ export default function ProfilePage() {
       const data = (await res.json().catch(() => null)) as {
         error?: { message?: string };
       } | null;
-      setError(data?.error?.message ?? '更新に失敗しました');
+      setError(data?.error?.message ?? t('auth.failed'));
     }
   }
 
@@ -55,61 +57,63 @@ export default function ProfilePage() {
 
   if (loading) {
     return (
-      <main className="flex min-h-screen items-center justify-center">
-        <p>読み込み中...</p>
+      <main className="flex min-h-screen items-center justify-center bg-gray-50 dark:bg-gray-900">
+        <p className="text-gray-500 dark:text-gray-400">
+          {t('common.loading')}
+        </p>
       </main>
     );
   }
 
   return (
-    <main className="min-h-screen bg-gray-50 p-8">
-      <div className="mx-auto max-w-md rounded-lg border bg-white p-8 shadow-sm">
+    <main className="min-h-screen bg-gray-50 p-8 dark:bg-gray-900">
+      <div className="mx-auto max-w-md rounded-lg border bg-white p-8 shadow-sm dark:border-gray-700 dark:bg-gray-800">
         <div className="flex items-center justify-between">
-          <h1 className="text-2xl font-bold">プロフィール</h1>
+          <h1 className="text-2xl font-bold">{t('profile.title')}</h1>
           <button
             type="button"
             onClick={onLogout}
-            className="text-sm text-blue-600 hover:underline"
+            className="text-sm text-blue-600 hover:underline dark:text-blue-400"
           >
-            ログアウト
+            {t('header.logout')}
           </button>
         </div>
 
         <form className="mt-6 space-y-4" onSubmit={onSubmit}>
           <div>
             <label htmlFor="name" className="block text-sm font-medium">
-              表示名
+              {t('profile.displayName')}
             </label>
             <input
               id="name"
               type="text"
               value={name}
               onChange={(e) => setName(e.target.value)}
-              className="mt-1 w-full rounded border px-3 py-2"
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
             />
           </div>
           <div>
             <label htmlFor="email" className="block text-sm font-medium">
-              メールアドレス
+              {t('profile.email')}
             </label>
             <input
               id="email"
               type="email"
               value={email}
               onChange={(e) => setEmail(e.target.value)}
-              className="mt-1 w-full rounded border px-3 py-2"
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
             />
           </div>
           <div>
             <label htmlFor="avatarUrl" className="block text-sm font-medium">
-              アイコン画像URL
+              {t('profile.avatarUrl')}
             </label>
             <input
               id="avatarUrl"
               type="url"
               value={avatarUrl}
               onChange={(e) => setAvatarUrl(e.target.value)}
-              className="mt-1 w-full rounded border px-3 py-2"
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
             />
           </div>
 
@@ -119,26 +123,64 @@ export default function ProfilePage() {
             </p>
           )}
           {saved && (
-            <p className="text-sm text-green-600">プロフィールを更新しました</p>
+            <p className="text-sm text-green-600">{t('profile.saved')}</p>
           )}
 
           <button
             type="submit"
             className="w-full rounded bg-blue-600 px-4 py-2 font-medium text-white hover:bg-blue-700"
           >
-            保存
+            {t('common.save')}
           </button>
         </form>
 
+        <div className="mt-6 space-y-3 border-t pt-4 dark:border-gray-700">
+          <div>
+            <label htmlFor="theme-select" className="block text-sm font-medium">
+              {t('profile.theme')}
+            </label>
+            <select
+              id="theme-select"
+              value={theme}
+              onChange={(e) =>
+                void setTheme(e.target.value as 'dark' | 'light')
+              }
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
+              data-testid="profile-theme-select"
+            >
+              <option value="dark">{t('theme.dark')}</option>
+              <option value="light">{t('theme.light')}</option>
+            </select>
+          </div>
+          <div>
+            <label
+              htmlFor="locale-select"
+              className="block text-sm font-medium"
+            >
+              {t('profile.language')}
+            </label>
+            <select
+              id="locale-select"
+              value={locale}
+              onChange={(e) => setLocale(e.target.value as 'en' | 'ja')}
+              className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
+              data-testid="profile-locale-select"
+            >
+              <option value="en">{t('language.english')}</option>
+              <option value="ja">{t('language.japanese')}</option>
+            </select>
+          </div>
+        </div>
+
         <button
           type="button"
           onClick={() => router.push('/dashboard')}
-          className="mt-4 w-full text-center text-sm text-blue-600 hover:underline"
+          className="mt-4 w-full text-center text-sm text-blue-600 hover:underline dark:text-blue-400"
         >
-          ダッシュボードへ
+          {t('profile.backToDashboard')}
         </button>
-        <p className="mt-2 text-center text-xs text-gray-500">
-          ロール: {user?.role}
+        <p className="mt-2 text-center text-xs text-gray-500 dark:text-gray-400">
+          {t('profile.role')}: {user?.role}
         </p>
       </div>
     </main>

app/projects/[projectId]/activity/page.tsx

@@ -50,24 +50,28 @@ export default async function ProjectActivityPage({
   const { items } = activityService.listByProject(project.id, 1);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="activity" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
         <h1 className="text-2xl font-bold">アクティビティログ</h1>
         {items.length === 0 ? (
-          <p className="text-sm text-gray-400">アクティビティはありません。</p>
+          <p className="text-sm text-gray-400 dark:text-gray-500">
+            アクティビティはありません。
+          </p>
         ) : (
-          <ul className="divide-y rounded-lg border bg-white shadow-sm">
+          <ul className="divide-y rounded-lg border bg-white dark:bg-gray-800 shadow-sm">
             {items.map((log) => (
               <li key={log.id} className="p-4">
                 <div className="flex items-center justify-between">
-                  <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+                  <span className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs">
                     {ACTION_LABELS[log.action] ?? log.action}
                   </span>
-                  <span className="text-xs text-gray-400">{log.createdAt}</span>
+                  <span className="text-xs text-gray-400 dark:text-gray-500">
+                    {log.createdAt}
+                  </span>
                 </div>
-                <p className="mt-2 text-sm text-gray-700">
+                <p className="mt-2 text-sm text-gray-700 dark:text-gray-200">
                   {log.targetType}
                   {log.targetId !== null ? ` #${log.targetId}` : ''}
                 </p>

app/projects/[projectId]/board/[threadId]/page.tsx

@@ -52,7 +52,7 @@ export default async function ThreadDetailPage({
   }
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={Number(projectId)} active="board" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -62,11 +62,11 @@ export default async function ThreadDetailPage({
         >
           ← 掲示板一覧へ
         </a>
-        <div className="rounded-lg border bg-white p-6 shadow-sm">
+        <div className="rounded-lg border bg-white dark:bg-gray-800 p-6 shadow-sm">
           <div className="flex items-center justify-between">
             <h1 className="text-2xl font-bold">{thread.title}</h1>
             {thread.category && (
-              <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+              <span className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs">
                 {thread.category}
               </span>
             )}
@@ -76,13 +76,13 @@ export default async function ThreadDetailPage({
           </div>
           {attachments.thread.length > 0 && (
             <div className="mt-4">
-              <p className="mb-1 text-xs font-medium text-gray-500">
+              <p className="mb-1 text-xs font-medium text-gray-500 dark:text-gray-400">
                 添付ファイル
               </p>
               <AttachmentList attachments={attachments.thread} />
             </div>
           )}
-          <p className="mt-4 text-xs text-gray-400">
+          <p className="mt-4 text-xs text-gray-400 dark:text-gray-500">
             投稿: {thread.createdAt} / 更新: {thread.updatedAt}
           </p>
         </div>
@@ -92,7 +92,7 @@ export default async function ThreadDetailPage({
           {comments.items.map((comment) => (
             <div
               key={comment.id}
-              className="rounded-lg border bg-white p-4 shadow-sm"
+              className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
             >
               <MarkdownBody bodyMd={comment.bodyMd} />
               {commentAttachments.has(comment.id) &&
@@ -103,7 +103,9 @@ export default async function ThreadDetailPage({
                     />
                   </div>
                 )}
-              <p className="mt-2 text-xs text-gray-400">{comment.createdAt}</p>
+              <p className="mt-2 text-xs text-gray-400 dark:text-gray-500">
+                {comment.createdAt}
+              </p>
             </div>
           ))}
           <CommentForm projectId={Number(projectId)} threadId={thread.id} />

app/projects/[projectId]/board/page.tsx

@@ -38,7 +38,7 @@ export default async function BoardPage({
   });
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="board" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -46,27 +46,31 @@ export default async function BoardPage({
         <ThreadForm projectId={project.id} />
         <section className="space-y-3">
           {items.length === 0 ? (
-            <p className="text-sm text-gray-400">スレッドはありません。</p>
+            <p className="text-sm text-gray-400 dark:text-gray-500">
+              スレッドはありません。
+            </p>
           ) : (
             items.map((thread) => (
               <a
                 key={thread.id}
                 href={`/projects/${project.id}/board/${thread.id}`}
-                className="block rounded-lg border bg-white p-4 shadow-sm hover:shadow-md"
+                className="block rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm hover:shadow-md"
               >
                 <div className="flex items-center justify-between">
-                  <h3 className="font-semibold text-gray-800">
+                  <h3 className="font-semibold text-gray-800 dark:text-gray-100">
                     {thread.isPinned === 1 && '📌 '}
                     {thread.isImportant === 1 && '❗ '}
                     {thread.title}
                   </h3>
                   {thread.category && (
-                    <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+                    <span className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs">
                       {thread.category}
                     </span>
                   )}
                 </div>
-                <p className="mt-1 text-xs text-gray-400">{thread.createdAt}</p>
+                <p className="mt-1 text-xs text-gray-400 dark:text-gray-500">
+                  {thread.createdAt}
+                </p>
               </a>
             ))
           )}

app/projects/[projectId]/calendar/page.tsx

@@ -60,7 +60,7 @@ export default async function CalendarPage({
   const events = scheduleService.getCalendarEvents(user.id, project.id, range);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="calendar" />
       <main className="mx-auto max-w-6xl space-y-6 p-6">

app/projects/[projectId]/chat/page.tsx

@@ -29,7 +29,7 @@ export default async function ChatPage({
   }
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="chat" />
       <main className="mx-auto max-w-3xl space-y-4 p-6">

app/projects/[projectId]/files/page.tsx

@@ -39,7 +39,7 @@ export default async function FilesPage({
     items.some((f) => f.uploaderId === user.id);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="files" />
       <main className="mx-auto max-w-4xl space-y-6 p-6">

app/projects/[projectId]/meetings/page.tsx

@@ -36,7 +36,7 @@ export default async function MeetingsPage({
   }));
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="meetings" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -44,23 +44,31 @@ export default async function MeetingsPage({
         <MeetingForm projectId={project.id} members={members} />
         <section className="space-y-3">
           {meetings.length === 0 ? (
-            <p className="text-sm text-gray-400">ミーティングはありません。</p>
+            <p className="text-sm text-gray-400 dark:text-gray-500">
+              ミーティングはありません。
+            </p>
           ) : (
             meetings.map((m) => (
               <div
                 key={m.id}
-                className="rounded-lg border bg-white p-4 shadow-sm"
+                className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
                 data-testid={`meeting-${m.id}`}
               >
-                <h3 className="font-semibold text-gray-800">{m.title}</h3>
-                <p className="text-xs text-gray-500">
+                <h3 className="font-semibold text-gray-800 dark:text-gray-100">
+                  {m.title}
+                </h3>
+                <p className="text-xs text-gray-500 dark:text-gray-400">
                   {m.startAt} 〜 {m.endAt}
                 </p>
                 {m.location && (
-                  <p className="text-xs text-gray-500">場所: {m.location}</p>
+                  <p className="text-xs text-gray-500 dark:text-gray-400">
+                    場所: {m.location}
+                  </p>
                 )}
                 {m.minutesMd && (
-                  <p className="mt-2 text-sm text-gray-600">議事録あり</p>
+                  <p className="mt-2 text-sm text-gray-600 dark:text-gray-300">
+                    議事録あり
+                  </p>
                 )}
               </div>
             ))

app/projects/[projectId]/members/page.tsx

@@ -38,7 +38,7 @@ export default async function ProjectMembersPage({
   }
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="members" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -46,7 +46,7 @@ export default async function ProjectMembersPage({
 
         {canManage && <AddMemberForm projectId={project.id} />}
 
-        <section className="rounded-lg border bg-white shadow-sm">
+        <section className="rounded-lg border bg-white dark:bg-gray-800 shadow-sm">
           <ul className="divide-y">
             {members.map((member) => (
               <li
@@ -54,18 +54,20 @@ export default async function ProjectMembersPage({
                 className="flex items-center justify-between p-4"
               >
                 <div>
-                  <p className="font-medium text-gray-800">
+                  <p className="font-medium text-gray-800 dark:text-gray-100">
                     {member.user.name}
                     {member.userId === user.id && (
-                      <span className="ml-2 text-xs text-gray-400">
+                      <span className="ml-2 text-xs text-gray-400 dark:text-gray-500">
                         (あなた)
                       </span>
                     )}
                   </p>
-                  <p className="text-sm text-gray-500">{member.user.email}</p>
+                  <p className="text-sm text-gray-500 dark:text-gray-400">
+                    {member.user.email}
+                  </p>
                 </div>
                 <div className="flex items-center gap-3">
-                  <span className="text-sm text-gray-600">
+                  <span className="text-sm text-gray-600 dark:text-gray-300">
                     {ROLE_LABEL[member.role] ?? member.role}
                   </span>
                   {canManage && member.userId !== user.id && (

app/projects/[projectId]/milestones/page.tsx

@@ -41,7 +41,7 @@ export default async function MilestonesPage({
   const milestones = scheduleService.getMilestones(user.id, project.id);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="milestones" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -49,34 +49,38 @@ export default async function MilestonesPage({
         <MilestoneForm projectId={project.id} />
         <section className="space-y-3">
           {milestones.length === 0 ? (
-            <p className="text-sm text-gray-400">
+            <p className="text-sm text-gray-400 dark:text-gray-500">
               マイルストーンはありません。
             </p>
           ) : (
             milestones.map((m) => (
               <div
                 key={m.id}
-                className="rounded-lg border bg-white p-4 shadow-sm"
+                className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
                 data-testid={`milestone-${m.id}`}
               >
                 <div className="flex items-center justify-between">
-                  <h3 className="font-semibold text-gray-800">{m.title}</h3>
-                  <span className="text-xs text-gray-500">
+                  <h3 className="font-semibold text-gray-800 dark:text-gray-100">
+                    {m.title}
+                  </h3>
+                  <span className="text-xs text-gray-500 dark:text-gray-400">
                     {m.status}
                     {m.dueDate ? ` / 期限: ${m.dueDate}` : ''}
                   </span>
                 </div>
                 {m.description && (
-                  <p className="mt-1 text-sm text-gray-600">{m.description}</p>
+                  <p className="mt-1 text-sm text-gray-600 dark:text-gray-300">
+                    {m.description}
+                  </p>
                 )}
                 <div className="mt-3">
-                  <div className="flex items-center justify-between text-xs text-gray-500">
+                  <div className="flex items-center justify-between text-xs text-gray-500 dark:text-gray-400">
                     <span>進捗</span>
                     <span data-testid={`milestone-progress-${m.id}`}>
                       {m.progress}%
                     </span>
                   </div>
-                  <div className="mt-1 h-2 w-full rounded bg-gray-200">
+                  <div className="mt-1 h-2 w-full rounded bg-gray-200 dark:bg-gray-700">
                     <div
                       className={`h-2 rounded ${progressColor(m.progress)}`}
                       style={{ width: `${m.progress}%` }}

app/projects/[projectId]/notes/[noteId]/page.tsx

@@ -31,7 +31,7 @@ export default async function NoteDetailPage({
   }
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={Number(projectId)} active="notes" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -41,18 +41,20 @@ export default async function NoteDetailPage({
         >
           ← メモ一覧へ
         </a>
-        <div className="rounded-lg border bg-white p-6 shadow-sm">
+        <div className="rounded-lg border bg-white dark:bg-gray-800 p-6 shadow-sm">
           <h1 className="text-2xl font-bold">
             {note.isPinned === 1 && '📌 '}
             {note.title}
           </h1>
           {note.tags && (
-            <p className="mt-1 text-xs text-gray-500">{note.tags}</p>
+            <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
+              {note.tags}
+            </p>
           )}
           <div className="mt-4">
             <MarkdownBody bodyMd={note.bodyMd} />
           </div>
-          <p className="mt-4 text-xs text-gray-400">
+          <p className="mt-4 text-xs text-gray-400 dark:text-gray-500">
             作成: {note.createdAt} / 更新: {note.updatedAt}
           </p>
         </div>

app/projects/[projectId]/notes/page.tsx

@@ -38,7 +38,7 @@ export default async function NotesPage({
   });
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="notes" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -46,24 +46,30 @@ export default async function NotesPage({
         <NoteForm projectId={project.id} />
         <section className="space-y-3">
           {items.length === 0 ? (
-            <p className="text-sm text-gray-400">メモはありません。</p>
+            <p className="text-sm text-gray-400 dark:text-gray-500">
+              メモはありません。
+            </p>
           ) : (
             items.map((note) => (
               <a
                 key={note.id}
                 href={`/projects/${project.id}/notes/${note.id}`}
-                className="block rounded-lg border bg-white p-4 shadow-sm hover:shadow-md"
+                className="block rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm hover:shadow-md"
               >
                 <div className="flex items-center justify-between">
-                  <h3 className="font-semibold text-gray-800">
+                  <h3 className="font-semibold text-gray-800 dark:text-gray-100">
                     {note.isPinned === 1 && '📌 '}
                     {note.title}
                   </h3>
                   {note.tags && (
-                    <span className="text-xs text-gray-500">{note.tags}</span>
+                    <span className="text-xs text-gray-500 dark:text-gray-400">
+                      {note.tags}
+                    </span>
                   )}
                 </div>
-                <p className="mt-1 text-xs text-gray-400">{note.updatedAt}</p>
+                <p className="mt-1 text-xs text-gray-400 dark:text-gray-500">
+                  {note.updatedAt}
+                </p>
               </a>
             ))
           )}

app/projects/[projectId]/page.tsx

@@ -31,18 +31,20 @@ export default async function ProjectOverviewPage({
   const { project } = dashboard;
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="overview" />
       <main className="mx-auto max-w-4xl space-y-6 p-6">
         <div className="flex items-center justify-between">
           <h1 className="text-2xl font-bold">{project.name}</h1>
-          <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+          <span className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs">
             {project.status}
           </span>
         </div>
         {project.description && (
-          <p className="text-gray-600">{project.description}</p>
+          <p className="text-gray-600 dark:text-gray-300">
+            {project.description}
+          </p>
         )}
 
         <div className="grid gap-4 sm:grid-cols-2">
@@ -119,7 +121,7 @@ export default async function ProjectOverviewPage({
                 <p className="text-sm">
                   {m.title} - {m.progress}%
                 </p>
-                <div className="h-1.5 w-full rounded bg-gray-200">
+                <div className="h-1.5 w-full rounded bg-gray-200 dark:bg-gray-700">
                   <div
                     className="h-1.5 rounded bg-blue-500"
                     style={{ width: `${m.progress}%` }}

app/projects/[projectId]/search/page.tsx

@@ -51,7 +51,7 @@ export default async function SearchPage({
     : [];
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="search" />
       <main className="mx-auto max-w-3xl space-y-6 p-6">
@@ -63,7 +63,9 @@ export default async function SearchPage({
         />
         <section className="space-y-2">
           {q && results.length === 0 && (
-            <p className="text-sm text-gray-400">該当する結果はありません。</p>
+            <p className="text-sm text-gray-400 dark:text-gray-500">
+              該当する結果はありません。
+            </p>
           )}
           {results.map((r) => {
             const href =
@@ -73,16 +75,20 @@ export default async function SearchPage({
               <a
                 key={`${r.type}-${r.id}`}
                 href={href}
-                className="block rounded border bg-white p-3 shadow-sm hover:shadow-md"
+                className="block rounded border bg-white dark:bg-gray-800 p-3 shadow-sm hover:shadow-md"
                 data-testid={`search-result-${r.type}-${r.id}`}
               >
                 <div className="flex items-center justify-between">
-                  <span className="font-medium text-gray-800">{r.title}</span>
-                  <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+                  <span className="font-medium text-gray-800 dark:text-gray-100">
+                    {r.title}
+                  </span>
+                  <span className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs">
                     {r.type}
                   </span>
                 </div>
-                <p className="mt-1 text-xs text-gray-500">{r.snippet}</p>
+                <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
+                  {r.snippet}
+                </p>
               </a>
             );
           })}

app/projects/[projectId]/settings/page.tsx

@@ -34,18 +34,18 @@ export default async function ProjectSettingsPage({
   }
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="settings" />
       <main className="mx-auto max-w-2xl space-y-6 p-6">
         <h1 className="text-2xl font-bold">プロジェクト設定</h1>
-        <div className="rounded-lg border bg-white p-6 shadow-sm">
+        <div className="rounded-lg border bg-white dark:bg-gray-800 p-6 shadow-sm">
           <ProjectSettingsForm project={project} canManage={canManage} />
         </div>
         {canManage && (
-          <div className="rounded-lg border border-red-200 bg-white p-6 shadow-sm">
+          <div className="rounded-lg border border-red-200 bg-white dark:bg-gray-800 p-6 shadow-sm">
             <h2 className="text-sm font-semibold text-red-700">危険操作</h2>
-            <p className="mt-1 text-sm text-gray-600">
+            <p className="mt-1 text-sm text-gray-600 dark:text-gray-300">
               プロジェクトを削除すると、関連データも削除されます。
             </p>
             <DeleteProjectButton projectId={project.id} />

app/projects/[projectId]/todos/page.tsx

@@ -31,9 +31,10 @@ export default async function TodosPage({
   const todoService = createTodoService();
   const columns = todoService.getColumns(user.id, project.id);
   const items = todoService.getItems(user.id, project.id);
+  const members = projectService.getMembers(user.id, project.id);
 
   return (
-    <div className="min-h-screen bg-gray-50">
+    <div className="min-h-screen bg-gray-50 dark:bg-gray-900">
       <Header user={toPublicUser(user)} />
       <ProjectNav projectId={project.id} active="todos" />
       <main className="space-y-4 p-6">
@@ -42,6 +43,7 @@ export default async function TodosPage({
           projectId={project.id}
           columns={columns}
           initialItems={items}
+          members={members}
         />
       </main>
     </div>

components/admin/BackupCreateButton.tsx

@@ -24,8 +24,8 @@ export function BackupCreateButton() {
   }
 
   return (
-    <div className="rounded-lg border bg-white p-4 shadow-sm">
-      <p className="text-sm text-gray-600">
+    <div className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm">
+      <p className="text-sm text-gray-600 dark:text-gray-300">
         DBファイル + uploadsディレクトリをZIP化してバックアップを作成します。
       </p>
       <button

components/board/ThreadForm.tsx

@@ -58,7 +58,7 @@ export function ThreadForm({ projectId }: { projectId: number }) {
   return (
     <form
       onSubmit={onSubmit}
-      className="space-y-3 rounded-lg border bg-white p-4 shadow-sm"
+      className="space-y-3 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
     >
       <div className="flex gap-2">
         <input

components/calendar/CalendarEventForm.tsx

@@ -40,7 +40,7 @@ export function CalendarEventForm({
   return (
     <form
       onSubmit={onSubmit}
-      className="flex flex-col gap-2 rounded-lg border bg-white p-4 shadow-sm sm:flex-row sm:items-end"
+      className="flex flex-col gap-2 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm sm:flex-row sm:items-end"
     >
       <div className="flex-1">
         <label className="block text-sm font-medium">イベント名</label>

components/calendar/CalendarView.tsx

@@ -80,7 +80,7 @@ export function CalendarView({
     <div className="space-y-4">
       <div className="flex flex-wrap items-center justify-between gap-2">
         <h2
-          className="text-xl font-bold text-gray-800"
+          className="text-xl font-bold text-gray-800 dark:text-gray-100"
           data-testid="calendar-title"
         >
           {title}
@@ -95,7 +95,7 @@ export function CalendarView({
                 className={`px-3 py-1 text-sm ${
                   view === v.mode
                     ? 'bg-blue-600 text-white'
-                    : 'bg-white text-gray-600 hover:bg-gray-100'
+                    : 'bg-white dark:bg-gray-800 text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700'
                 }`}
                 data-testid={`calendar-view-${v.mode}`}
               >
@@ -107,7 +107,7 @@ export function CalendarView({
             <button
               type="button"
               onClick={goPrev}
-              className="rounded border bg-white px-2 py-1 text-sm text-gray-600 hover:bg-gray-100"
+              className="rounded border bg-white dark:bg-gray-800 px-2 py-1 text-sm text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
               aria-label="前へ"
               data-testid="calendar-prev"
             >
@@ -116,7 +116,7 @@ export function CalendarView({
             <button
               type="button"
               onClick={goToday}
-              className="rounded border bg-white px-3 py-1 text-sm text-gray-600 hover:bg-gray-100"
+              className="rounded border bg-white dark:bg-gray-800 px-3 py-1 text-sm text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
               data-testid="calendar-today"
             >
               今日
@@ -124,7 +124,7 @@ export function CalendarView({
             <button
               type="button"
               onClick={goNext}
-              className="rounded border bg-white px-2 py-1 text-sm text-gray-600 hover:bg-gray-100"
+              className="rounded border bg-white dark:bg-gray-800 px-2 py-1 text-sm text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
               aria-label="次へ"
               data-testid="calendar-next"
             >

components/calendar/DayView.tsx

@@ -37,14 +37,14 @@ export function DayView({
   const isToday = key === todayKey;
 
   return (
-    <div className="rounded-lg border bg-white">
+    <div className="rounded-lg border bg-white dark:bg-gray-800">
       <div className="flex items-center justify-between border-b p-3">
         <button
           type="button"
           onClick={() => onSelectDate(key)}
           className="text-left"
         >
-          <p className="text-lg font-bold text-gray-800">
+          <p className="text-lg font-bold text-gray-800 dark:text-gray-100">
             {day.getMonth() + 1}月{day.getDate()}日(
             {WEEKDAY_LABELS[day.getDay()]})
           </p>
@@ -58,10 +58,12 @@ export function DayView({
 
       {allDay.length > 0 && (
         <div
-          className="border-b bg-gray-50 p-2"
+          className="border-b bg-gray-50 dark:bg-gray-900 p-2"
           data-testid="calendar-all-day-section"
         >
-          <p className="mb-1 text-xs font-medium text-gray-500">終日</p>
+          <p className="mb-1 text-xs font-medium text-gray-500 dark:text-gray-400">
+            終日
+          </p>
           <div className="flex flex-wrap gap-1">
             {allDay.map((e) => (
               <button
@@ -70,8 +72,9 @@ export function DayView({
                 onClick={() => onSelectDate(key)}
                 title={e.title}
                 className={`max-w-full truncate rounded border px-2 py-0.5 text-xs ${
-                  SOURCE_COLORS[e.source] ?? 'bg-gray-100 text-gray-600'
-                } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200'}`}
+                  SOURCE_COLORS[e.source] ??
+                  'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300'
+                } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200 dark:border-gray-700'}`}
                 data-testid={`calendar-event-${e.key}`}
               >
                 {e.title}
@@ -90,7 +93,7 @@ export function DayView({
               className="flex border-b last:border-b-0"
               data-testid={`calendar-hour-${String(h).padStart(2, '0')}`}
             >
-              <div className="w-16 shrink-0 border-r bg-gray-50 p-1 text-right text-xs text-gray-400">
+              <div className="w-16 shrink-0 border-r bg-gray-50 dark:bg-gray-900 p-1 text-right text-xs text-gray-400 dark:text-gray-500">
                 {String(h).padStart(2, '0')}:00
               </div>
               <div className="flex-1 p-1">
@@ -101,8 +104,9 @@ export function DayView({
                     onClick={() => onSelectDate(key)}
                     title={e.title}
                     className={`mb-1 block w-full truncate rounded border px-2 py-1 text-left text-xs ${
-                      SOURCE_COLORS[e.source] ?? 'bg-gray-100 text-gray-600'
-                    } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200'}`}
+                      SOURCE_COLORS[e.source] ??
+                      'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300'
+                    } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200 dark:border-gray-700'}`}
                     data-testid={`calendar-event-${e.key}`}
                   >
                     <span className="font-mono text-[10px] opacity-70">

components/calendar/EventDetailDialog.tsx

@@ -51,7 +51,7 @@ export function EventDetailDialog({
       <div
         ref={dialogRef}
         tabIndex={-1}
-        className="mt-16 w-full max-w-lg rounded-lg bg-white shadow-xl focus:outline-none"
+        className="mt-16 w-full max-w-lg rounded-lg bg-white dark:bg-gray-800 shadow-xl focus:outline-none"
         onClick={(e) => e.stopPropagation()}
         role="dialog"
         aria-modal="true"
@@ -59,11 +59,13 @@ export function EventDetailDialog({
         data-testid="calendar-detail-dialog"
       >
         <div className="flex items-center justify-between border-b p-4">
-          <h2 className="text-lg font-bold text-gray-800">{dateLabel}</h2>
+          <h2 className="text-lg font-bold text-gray-800 dark:text-gray-100">
+            {dateLabel}
+          </h2>
           <button
             type="button"
             onClick={onClose}
-            className="rounded p-1 text-gray-400 hover:bg-gray-100 hover:text-gray-600"
+            className="rounded p-1 text-gray-400 dark:text-gray-500 hover:bg-gray-100 dark:hover:bg-gray-700 hover:text-gray-600"
             aria-label="閉じる"
             data-testid="calendar-detail-close"
           >
@@ -72,34 +74,35 @@ export function EventDetailDialog({
         </div>
         <div className="max-h-[60vh] space-y-3 overflow-y-auto p-4">
           {events.length === 0 ? (
-            <p className="text-sm text-gray-400">
+            <p className="text-sm text-gray-400 dark:text-gray-500">
               この日のイベントはありません。
             </p>
           ) : (
             events.map((e) => (
               <div
                 key={e.key}
-                className="rounded border border-gray-200 p-3"
+                className="rounded border border-gray-200 dark:border-gray-700 p-3"
                 data-testid={`calendar-detail-${e.key}`}
               >
                 <div className="flex items-center justify-between gap-2">
-                  <p className="font-medium text-gray-800 break-words">
+                  <p className="font-medium text-gray-800 dark:text-gray-100 break-words">
                     {e.title}
                   </p>
                   <span
                     className={`shrink-0 rounded px-2 py-0.5 text-xs ${
-                      SOURCE_COLORS[e.source] ?? 'bg-gray-100 text-gray-600'
+                      SOURCE_COLORS[e.source] ??
+                      'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300'
                     }`}
                   >
                     {SOURCE_LABELS[e.source] ?? e.source}
                   </span>
                 </div>
-                <p className="mt-1 text-xs text-gray-500">
+                <p className="mt-1 text-xs text-gray-500 dark:text-gray-400">
                   {formatTime(e.startAt)}
                   {e.endAt ? ` 〜 ${formatTime(e.endAt)}` : ''}
                 </p>
                 {e.description && (
-                  <p className="mt-2 whitespace-pre-wrap text-sm text-gray-600">
+                  <p className="mt-2 whitespace-pre-wrap text-sm text-gray-600 dark:text-gray-300">
                     {e.description}
                   </p>
                 )}

components/calendar/MilestoneForm.tsx

@@ -35,7 +35,7 @@ export function MilestoneForm({ projectId }: { projectId: number }) {
   return (
     <form
       onSubmit={onSubmit}
-      className="flex flex-col gap-2 rounded-lg border bg-white p-4 shadow-sm sm:flex-row sm:items-end"
+      className="flex flex-col gap-2 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm sm:flex-row sm:items-end"
     >
       <div className="flex-1">
         <label className="block text-sm font-medium">マイルストーン名</label>

components/calendar/MonthView.tsx

@@ -28,8 +28,8 @@ export function MonthView({
   onSelectDate: (dateKey: string) => void;
 }) {
   return (
-    <div className="overflow-hidden rounded-lg border bg-white">
-      <div className="grid grid-cols-7 border-b bg-gray-50 text-center text-xs font-medium text-gray-500">
+    <div className="overflow-hidden rounded-lg border bg-white dark:bg-gray-800">
+      <div className="grid grid-cols-7 border-b bg-gray-50 dark:bg-gray-900 text-center text-xs font-medium text-gray-500 dark:text-gray-400">
         {WEEKDAY_LABELS.map((w) => (
           <div key={w} className="py-2">
             {w}
@@ -50,7 +50,9 @@ export function MonthView({
                 <div
                   key={key}
                   className={`min-h-[110px] border-r border-t p-1 last:border-r-0 ${
-                    inMonth ? 'bg-white' : 'bg-gray-50'
+                    inMonth
+                      ? 'bg-white dark:bg-gray-800'
+                      : 'bg-gray-50 dark:bg-gray-900'
                   }`}
                   data-testid={`calendar-day-${key}`}
                 >
@@ -61,8 +63,8 @@ export function MonthView({
                       isToday
                         ? 'bg-blue-600 font-bold text-white'
                         : inMonth
-                          ? 'text-gray-700 hover:bg-gray-100'
-                          : 'text-gray-300 hover:bg-gray-100'
+                          ? 'text-gray-700 dark:text-gray-200 hover:bg-gray-100 dark:hover:bg-gray-700'
+                          : 'text-gray-300 dark:text-gray-600 hover:bg-gray-100 dark:hover:bg-gray-700'
                     }`}
                     aria-label={`${key} の詳細を開く`}
                   >
@@ -76,8 +78,9 @@ export function MonthView({
                         onClick={() => onSelectDate(key)}
                         title={e.title}
                         className={`block w-full truncate rounded border px-1 text-left text-xs ${
-                          SOURCE_COLORS[e.source] ?? 'bg-gray-100 text-gray-600'
-                        } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200'}`}
+                          SOURCE_COLORS[e.source] ??
+                          'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300'
+                        } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200 dark:border-gray-700'}`}
                         data-testid={`calendar-event-${e.key}`}
                       >
                         {e.title}
@@ -88,7 +91,7 @@ export function MonthView({
                         type="button"
                         onClick={() => onSelectDate(key)}
                         aria-label={`${key}の残り${hidden}件を開く`}
-                        className="block w-full truncate text-left text-xs text-gray-400 hover:text-gray-600"
+                        className="block w-full truncate text-left text-xs text-gray-400 dark:text-gray-500 hover:text-gray-600"
                       >
                         +{hidden}件
                       </button>

components/calendar/WeekView.tsx

@@ -23,8 +23,8 @@ export function WeekView({
   onSelectDate: (dateKey: string) => void;
 }) {
   return (
-    <div className="overflow-hidden rounded-lg border bg-white">
-      <div className="grid grid-cols-7 border-b bg-gray-50 text-center text-xs font-medium text-gray-500">
+    <div className="overflow-hidden rounded-lg border bg-white dark:bg-gray-800">
+      <div className="grid grid-cols-7 border-b bg-gray-50 dark:bg-gray-900 text-center text-xs font-medium text-gray-500 dark:text-gray-400">
         {days.map((d) => {
           const key = toISODate(d);
           return (
@@ -32,15 +32,17 @@ export function WeekView({
               key={key}
               type="button"
               onClick={() => onSelectDate(key)}
-              className="py-2 hover:bg-gray-100"
+              className="py-2 hover:bg-gray-100 dark:hover:bg-gray-700"
               data-testid={`calendar-weekday-${key}`}
             >
-              <div className="text-gray-500">{WEEKDAY_LABELS[d.getDay()]}</div>
+              <div className="text-gray-500 dark:text-gray-400">
+                {WEEKDAY_LABELS[d.getDay()]}
+              </div>
               <div
                 className={`mt-0.5 inline-flex h-6 w-6 items-center justify-center rounded-full text-sm ${
                   key === todayKey
                     ? 'bg-blue-600 font-bold text-white'
-                    : 'text-gray-700'
+                    : 'text-gray-700 dark:text-gray-200'
                 }`}
               >
                 {d.getDate()}
@@ -61,7 +63,9 @@ export function WeekView({
             >
               <div className="space-y-1">
                 {dayEvents.length === 0 ? (
-                  <p className="px-1 py-1 text-xs text-gray-300">-</p>
+                  <p className="px-1 py-1 text-xs text-gray-300 dark:text-gray-600">
+                    -
+                  </p>
                 ) : (
                   dayEvents.map((e) => (
                     <button
@@ -70,8 +74,9 @@ export function WeekView({
                       onClick={() => onSelectDate(key)}
                       title={e.title}
                       className={`block w-full truncate rounded border px-1 py-0.5 text-left text-xs ${
-                        SOURCE_COLORS[e.source] ?? 'bg-gray-100 text-gray-600'
-                      } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200'}`}
+                        SOURCE_COLORS[e.source] ??
+                        'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300'
+                      } ${SOURCE_CHIP_BORDER[e.source] ?? 'border-gray-200 dark:border-gray-700'}`}
                       data-testid={`calendar-event-${e.key}`}
                     >
                       <span className="font-mono text-[10px] opacity-70">

components/chat/ChatWindow.tsx

@@ -81,8 +81,19 @@ export function ChatWindow({ projectId, userName }: ChatWindowProps) {
       headers: { 'Content-Type': 'application/json' },
       body: JSON.stringify({ body: input, fileIds }),
     });
-    setSending(false);
     if (res.ok) {
+      // 送信したメッセージを即座に表示(SSE到着前でも見えるように楽観追加)。
+      // SSEの chat.message.created は id で重複排除する。
+      const data = (await res.json().catch(() => null)) as {
+        message?: ChatMessageWithAttachments;
+      } | null;
+      if (data?.message) {
+        setMessages((prev) =>
+          prev.some((m) => m.id === data.message!.id)
+            ? prev
+            : [data.message!, ...prev]
+        );
+      }
       setInput('');
       pickerRef.current?.clear();
     } else {
@@ -91,10 +102,11 @@ export function ChatWindow({ projectId, userName }: ChatWindowProps) {
       } | null;
       setError(b?.error?.message ?? '送信に失敗しました');
     }
+    setSending(false);
   }
 
   return (
-    <div className="flex h-[70vh] flex-col rounded-lg border bg-white shadow-sm">
+    <div className="flex h-[70vh] flex-col rounded-lg border bg-white dark:bg-gray-800 shadow-sm">
       <div className="flex-1 overflow-y-auto p-4">
         <ul className="space-y-2" data-testid="chat-messages">
           {messages.map((m) => (
@@ -106,8 +118,8 @@ export function ChatWindow({ projectId, userName }: ChatWindowProps) {
               <span
                 className={`max-w-[80%] rounded-lg px-3 py-2 ${
                   m.body.includes(`@${userName}`)
-                    ? 'bg-yellow-100 text-gray-800'
-                    : 'bg-gray-100 text-gray-800'
+                    ? 'bg-yellow-100 text-gray-800 dark:text-gray-100'
+                    : 'bg-gray-100 dark:bg-gray-700 text-gray-800 dark:text-gray-100'
                 }`}
               >
                 {m.body}
@@ -117,7 +129,7 @@ export function ChatWindow({ projectId, userName }: ChatWindowProps) {
                   <AttachmentList attachments={m.attachments} />
                 </div>
               )}
-              <span className="mt-0.5 text-xs text-gray-400">
+              <span className="mt-0.5 text-xs text-gray-400 dark:text-gray-500">
                 {m.createdAt}
               </span>
             </li>

components/files/AttachmentList.tsx

@@ -34,7 +34,7 @@ export function AttachmentList({
           return (
             <li
               key={a.id}
-              className="overflow-hidden rounded border bg-gray-50"
+              className="overflow-hidden rounded border bg-gray-50 dark:bg-gray-900"
               data-testid={`attachment-${a.id}`}
             >
               {isImage ? (

components/files/AttachmentPicker.tsx

@@ -98,7 +98,7 @@ export const AttachmentPicker = forwardRef<
 
   return (
     <div className="space-y-2" data-testid="attachment-picker">
-      <label className="inline-flex cursor-pointer items-center gap-1 rounded border bg-white px-3 py-1 text-sm text-gray-600 hover:bg-gray-100">
+      <label className="inline-flex cursor-pointer items-center gap-1 rounded border bg-white dark:bg-gray-800 px-3 py-1 text-sm text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700">
         📎 添付
         <input
           ref={inputRef}
@@ -111,7 +111,10 @@ export const AttachmentPicker = forwardRef<
         />
       </label>
       {loading && (
-        <p className="text-xs text-gray-500" data-testid="attachment-loading">
+        <p
+          className="text-xs text-gray-500 dark:text-gray-400"
+          data-testid="attachment-loading"
+        >
           アップロード中...
         </p>
       )}
@@ -128,7 +131,7 @@ export const AttachmentPicker = forwardRef<
             return (
               <li
                 key={f.fileId}
-                className="relative overflow-hidden rounded border bg-gray-50"
+                className="relative overflow-hidden rounded border bg-gray-50 dark:bg-gray-900"
                 data-testid={`attachment-picked-${f.fileId}`}
               >
                 {isImage ? (

components/files/FileList.tsx

@@ -20,7 +20,11 @@ export function FileList({
   }
 
   if (files.length === 0) {
-    return <p className="text-sm text-gray-400">ファイルはありません。</p>;
+    return (
+      <p className="text-sm text-gray-400 dark:text-gray-500">
+        ファイルはありません。
+      </p>
+    );
   }
 
   return (
@@ -36,7 +40,7 @@ export function FileList({
           return (
             <li
               key={file.id}
-              className="rounded-lg border bg-white p-3 shadow-sm"
+              className="rounded-lg border bg-white dark:bg-gray-800 p-3 shadow-sm"
               data-testid={`file-item-${file.id}`}
             >
               {isImage ? (
@@ -56,25 +60,27 @@ export function FileList({
                   href={url}
                   target="_blank"
                   rel="noreferrer"
-                  className="flex h-24 items-center justify-center rounded bg-gray-100 text-sm text-blue-600 hover:underline"
+                  className="flex h-24 items-center justify-center rounded bg-gray-100 dark:bg-gray-700 text-sm text-blue-600 hover:underline"
                 >
                   PDF を開く
                 </a>
               ) : (
                 <a
                   href={url}
-                  className="flex h-24 items-center justify-center rounded bg-gray-100 text-sm text-blue-600 hover:underline"
+                  className="flex h-24 items-center justify-center rounded bg-gray-100 dark:bg-gray-700 text-sm text-blue-600 hover:underline"
                 >
                   ダウンロード
                 </a>
               )}
               <p
-                className="mt-2 truncate text-xs text-gray-700"
+                className="mt-2 truncate text-xs text-gray-700 dark:text-gray-200"
                 title={file.originalName}
               >
                 {file.originalName}
               </p>
-              <p className="text-xs text-gray-400">{file.size} bytes</p>
+              <p className="text-xs text-gray-400 dark:text-gray-500">
+                {file.size} bytes
+              </p>
               {canDelete && (
                 <button
                   type="button"

components/files/Uploader.tsx

@@ -33,7 +33,7 @@ export function Uploader({ projectId }: { projectId: number }) {
   }
 
   return (
-    <div className="rounded-lg border bg-white p-4 shadow-sm">
+    <div className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm">
       <label className="block text-sm font-medium">
         ファイルをアップロード
       </label>
@@ -46,7 +46,9 @@ export function Uploader({ projectId }: { projectId: number }) {
         data-testid="file-input"
       />
       {loading && (
-        <p className="mt-1 text-sm text-gray-500">アップロード中...</p>
+        <p className="mt-1 text-sm text-gray-500 dark:text-gray-400">
+          アップロード中...
+        </p>
       )}
       {error && (
         <p className="mt-1 text-sm text-red-600" role="alert">

components/layout/Header.tsx

@@ -3,9 +3,12 @@
 import { useRouter } from 'next/navigation';
 import type { PublicUser } from '@/lib/auth/getCurrentUser';
 import { NotificationBadge } from '@/components/notifications/NotificationBadge';
+import { ThemeToggle } from '@/components/layout/ThemeToggle';
+import { useI18n } from '@/lib/i18n/I18nProvider';
 
 export function Header({ user }: { user: PublicUser }) {
   const router = useRouter();
+  const { t } = useI18n();
 
   async function handleLogout() {
     await fetch('/api/auth/logout', { method: 'POST' });
@@ -14,24 +17,34 @@ export function Header({ user }: { user: PublicUser }) {
   }
 
   return (
-    <header className="flex items-center justify-between border-b bg-white px-6 py-3">
-      <a href="/dashboard" className="font-bold text-gray-800">
-        シンプルグループウェア
+    <header className="flex items-center justify-between border-b bg-white px-6 py-3 dark:border-gray-700 dark:bg-gray-800">
+      <a
+        href="/dashboard"
+        className="font-bold text-gray-800 dark:text-gray-100"
+      >
+        {t('app.name')}
       </a>
-      <nav className="flex items-center gap-4 text-sm">
-        <a href="/dashboard" className="text-gray-600 hover:underline">
-          ダッシュボード
+      <nav className="flex items-center gap-3 text-sm sm:gap-4">
+        <a
+          href="/dashboard"
+          className="hidden text-gray-600 hover:underline sm:inline dark:text-gray-300"
+        >
+          {t('nav.dashboard')}
         </a>
+        <ThemeToggle />
         <NotificationBadge />
-        <a href="/profile" className="text-gray-600 hover:underline">
-          {user.name} さん
+        <a
+          href="/profile"
+          className="text-gray-600 hover:underline dark:text-gray-300"
+        >
+          {user.name}
         </a>
         <button
           type="button"
           onClick={handleLogout}
-          className="text-blue-600 hover:underline"
+          className="text-blue-600 hover:underline dark:text-blue-400"
         >
-          ログアウト
+          {t('header.logout')}
         </button>
       </nav>
     </header>

components/layout/ProjectNav.tsx

@@ -1,18 +1,23 @@
-const NAV_ITEMS = [
-  { href: '', label: '概要' },
-  { href: '/board', label: '掲示板' },
-  { href: '/notes', label: 'メモ' },
-  { href: '/chat', label: 'チャット' },
-  { href: '/todos', label: 'ToDo' },
-  { href: '/files', label: 'ファイル' },
-  { href: '/calendar', label: 'カレンダー' },
-  { href: '/milestones', label: 'マイルストーン' },
-  { href: '/meetings', label: 'ミーティング' },
-  { href: '/search', label: '検索' },
-  { href: '/members', label: 'メンバー' },
-  { href: '/activity', label: 'アクティビティ' },
-  { href: '/settings', label: '設定' },
-] as const;
+'use client';
+
+import { useI18n } from '@/lib/i18n/I18nProvider';
+import type { MessageKey } from '@/lib/i18n/dictionary';
+
+const NAV_ITEMS: { href: string; key: MessageKey; activeKey: string }[] = [
+  { href: '', key: 'nav.overview', activeKey: 'overview' },
+  { href: '/board', key: 'nav.board', activeKey: 'board' },
+  { href: '/notes', key: 'nav.notes', activeKey: 'notes' },
+  { href: '/chat', key: 'nav.chat', activeKey: 'chat' },
+  { href: '/todos', key: 'nav.todos', activeKey: 'todos' },
+  { href: '/files', key: 'nav.files', activeKey: 'files' },
+  { href: '/calendar', key: 'nav.calendar', activeKey: 'calendar' },
+  { href: '/milestones', key: 'nav.milestones', activeKey: 'milestones' },
+  { href: '/meetings', key: 'nav.meetings', activeKey: 'meetings' },
+  { href: '/search', key: 'nav.search', activeKey: 'search' },
+  { href: '/members', key: 'nav.members', activeKey: 'members' },
+  { href: '/activity', key: 'nav.activity', activeKey: 'activity' },
+  { href: '/settings', key: 'nav.settings', activeKey: 'settings' },
+];
 
 /**
  * プロジェクト内サブナビゲーション。
@@ -38,38 +43,26 @@ export function ProjectNav({
     | 'activity'
     | 'settings';
 }) {
-  const activeMap: Record<string, boolean> = {
-    overview: active === 'overview',
-    board: active === 'board',
-    notes: active === 'notes',
-    chat: active === 'chat',
-    todos: active === 'todos',
-    files: active === 'files',
-    calendar: active === 'calendar',
-    milestones: active === 'milestones',
-    meetings: active === 'meetings',
-    search: active === 'search',
-    members: active === 'members',
-    activity: active === 'activity',
-    settings: active === 'settings',
-  };
+  const { t } = useI18n();
 
   return (
-    <nav className="flex gap-4 border-b bg-white px-6 py-2 text-sm">
+    <nav
+      data-testid="project-nav"
+      className="flex gap-4 overflow-x-auto whitespace-nowrap border-b bg-white px-6 py-2 text-sm dark:border-gray-700 dark:bg-gray-800"
+    >
       {NAV_ITEMS.map((item) => {
-        const key = item.href === '' ? 'overview' : item.href.slice(1);
         const href = `/projects/${projectId}${item.href}`;
         return (
           <a
             key={item.href}
             href={href}
             className={
-              activeMap[key]
-                ? 'font-medium text-blue-600'
-                : 'text-gray-600 hover:underline'
+              active === item.activeKey
+                ? 'font-medium text-blue-600 dark:text-blue-400'
+                : 'text-gray-600 hover:underline dark:text-gray-300'
             }
           >
-            {item.label}
+            {t(item.key)}
           </a>
         );
       })}

components/layout/Sidebar.tsx

@@ -4,6 +4,8 @@
  */
 export function Sidebar({ children }: { children: React.ReactNode }) {
   return (
-    <aside className="w-48 shrink-0 border-r bg-gray-50 p-4">{children}</aside>
+    <aside className="w-48 shrink-0 border-r bg-gray-50 dark:bg-gray-900 p-4">
+      {children}
+    </aside>
   );
 }

components/layout/ThemeToggle.tsx

@@ -0,0 +1,24 @@
+'use client';
+
+import { useI18n } from '@/lib/i18n/I18nProvider';
+
+/**
+ * ヘッダー等に置くテーマ切替ボタン。
+ * クリックで dark/light を即時切替(Cookie + ユーザー設定へ永続化)。
+ */
+export function ThemeToggle() {
+  const { theme, setTheme } = useI18n();
+  const next = theme === 'dark' ? 'light' : 'dark';
+
+  return (
+    <button
+      type="button"
+      onClick={() => void setTheme(next)}
+      aria-label={theme === 'dark' ? 'Switch to light' : 'Switch to dark'}
+      data-testid="theme-toggle"
+      className="rounded px-2 py-1 text-sm text-gray-600 hover:underline dark:text-gray-300"
+    >
+      {theme === 'dark' ? '☀️' : '🌙'}
+    </button>
+  );
+}

components/meetings/MeetingForm.tsx

@@ -69,7 +69,7 @@ export function MeetingForm({
   return (
     <form
       onSubmit={onSubmit}
-      className="space-y-3 rounded-lg border bg-white p-4 shadow-sm"
+      className="space-y-3 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
       data-testid="meeting-form"
     >
       <div>

components/notes/NoteEditor.tsx

@@ -50,9 +50,11 @@ export function NoteEditor({
   return (
     <form
       onSubmit={onSubmit}
-      className="space-y-3 rounded-lg border bg-white p-4 shadow-sm"
+      className="space-y-3 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
     >
-      <h2 className="text-sm font-semibold text-gray-700">編集</h2>
+      <h2 className="text-sm font-semibold text-gray-700 dark:text-gray-200">
+        編集
+      </h2>
       <input
         type="text"
         value={title}

components/notes/NoteForm.tsx

@@ -36,7 +36,7 @@ export function NoteForm({ projectId }: { projectId: number }) {
   return (
     <form
       onSubmit={onSubmit}
-      className="space-y-3 rounded-lg border bg-white p-4 shadow-sm"
+      className="space-y-3 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm"
     >
       <input
         type="text"

components/notifications/MarkReadButton.tsx

@@ -23,7 +23,7 @@ export function MarkReadButton({ notificationId }: { notificationId: number }) {
       type="button"
       onClick={onRead}
       disabled={busy}
-      className="text-xs text-gray-500 hover:underline disabled:opacity-50"
+      className="text-xs text-gray-500 dark:text-gray-400 hover:underline disabled:opacity-50"
     >
       {busy ? '処理中...' : '既読にする'}
     </button>

components/notifications/NotificationBadge.tsx

@@ -22,7 +22,10 @@ export function NotificationBadge() {
 
   if (count === 0) {
     return (
-      <a href="/notifications" className="text-gray-600 hover:underline">
+      <a
+        href="/notifications"
+        className="text-gray-600 dark:text-gray-300 hover:underline"
+      >
         通知
       </a>
     );
@@ -31,7 +34,7 @@ export function NotificationBadge() {
   return (
     <a
       href="/notifications"
-      className="relative text-gray-600 hover:underline"
+      className="relative text-gray-600 dark:text-gray-300 hover:underline"
       data-notification-count={count}
     >
       通知

components/notifications/NotificationList.tsx

@@ -18,11 +18,15 @@ export function NotificationList({
   notifications: Notification[];
 }) {
   if (notifications.length === 0) {
-    return <p className="text-sm text-gray-400">未読の通知はありません。</p>;
+    return (
+      <p className="text-sm text-gray-400 dark:text-gray-500">
+        未読の通知はありません。
+      </p>
+    );
   }
 
   return (
-    <ul className="divide-y rounded-lg border bg-white shadow-sm">
+    <ul className="divide-y rounded-lg border bg-white dark:bg-gray-800 shadow-sm">
       {notifications.map((notification) => (
         <li key={notification.id} className="p-4">
           <div className="flex items-center justify-between">
@@ -31,9 +35,13 @@ export function NotificationList({
             </span>
             <MarkReadButton notificationId={notification.id} />
           </div>
-          <p className="mt-2 font-medium text-gray-800">{notification.title}</p>
+          <p className="mt-2 font-medium text-gray-800 dark:text-gray-100">
+            {notification.title}
+          </p>
           {notification.body && (
-            <p className="mt-1 text-sm text-gray-600">{notification.body}</p>
+            <p className="mt-1 text-sm text-gray-600 dark:text-gray-300">
+              {notification.body}
+            </p>
           )}
           {notification.projectId !== null && (
             <a

components/project/AddMemberForm.tsx

@@ -37,7 +37,7 @@ export function AddMemberForm({ projectId }: { projectId: number }) {
   return (
     <form
       onSubmit={onSubmit}
-      className="flex flex-col gap-2 rounded border bg-white p-4 sm:flex-row sm:items-end"
+      className="flex flex-col gap-2 rounded border bg-white dark:bg-gray-800 p-4 sm:flex-row sm:items-end"
     >
       <div className="flex-1">
         <label htmlFor="member-email" className="block text-sm font-medium">

components/project/CreateProjectForm.tsx

@@ -2,9 +2,11 @@
 
 import { useState, type FormEvent } from 'react';
 import { useRouter } from 'next/navigation';
+import { useI18n } from '@/lib/i18n/I18nProvider';
 
 export function CreateProjectForm() {
   const router = useRouter();
+  const { t } = useI18n();
   const [name, setName] = useState('');
   const [description, setDescription] = useState('');
   const [error, setError] = useState<string | null>(null);
@@ -30,25 +32,25 @@ export function CreateProjectForm() {
     const body = (await res.json().catch(() => null)) as {
       error?: { message?: string };
     } | null;
-    setError(body?.error?.message ?? 'プロジェクトの作成に失敗しました');
+    setError(body?.error?.message ?? t('project.createFailed'));
     setLoading(false);
   }
 
   return (
     <form
       onSubmit={onSubmit}
-      className="flex flex-col gap-2 rounded-lg border bg-white p-4 shadow-sm sm:flex-row sm:items-end"
+      className="flex flex-col gap-2 rounded-lg border bg-white p-4 shadow-sm sm:flex-row sm:items-end dark:border-gray-700 dark:bg-gray-800"
     >
       <div className="flex-1">
         <label htmlFor="project-name" className="block text-sm font-medium">
-          プロジェクト名
+          {t('auth.projectName')}
         </label>
         <input
           id="project-name"
           type="text"
           value={name}
           onChange={(e) => setName(e.target.value)}
-          className="mt-1 w-full rounded border px-3 py-2"
+          className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
           required
           maxLength={200}
         />
@@ -58,14 +60,14 @@ export function CreateProjectForm() {
           htmlFor="project-description"
           className="block text-sm font-medium"
         >
-          説明（任意）
+          {t('project.description')}
         </label>
         <input
           id="project-description"
           type="text"
           value={description}
           onChange={(e) => setDescription(e.target.value)}
-          className="mt-1 w-full rounded border px-3 py-2"
+          className="mt-1 w-full rounded border px-3 py-2 dark:border-gray-600 dark:bg-gray-700"
         />
       </div>
       <button
@@ -73,7 +75,7 @@ export function CreateProjectForm() {
         disabled={loading}
         className="rounded bg-blue-600 px-4 py-2 font-medium text-white hover:bg-blue-700 disabled:opacity-50"
       >
-        {loading ? '作成中...' : '新規プロジェクト'}
+        {loading ? t('project.creating') : t('auth.newProject')}
       </button>
       {error && (
         <p className="text-sm text-red-600 sm:full" role="alert">

components/project/DashboardWidget.tsx

@@ -12,12 +12,16 @@ export function DashboardWidget({
   empty?: string;
 }) {
   return (
-    <section className="rounded-lg border bg-white p-4 shadow-sm">
-      <h2 className="mb-3 text-sm font-semibold text-gray-700">{title}</h2>
+    <section className="rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm">
+      <h2 className="mb-3 text-sm font-semibold text-gray-700 dark:text-gray-200">
+        {title}
+      </h2>
       {children ? (
         <div className="space-y-2">{children}</div>
       ) : (
-        <p className="text-sm text-gray-400">{empty ?? 'データがありません'}</p>
+        <p className="text-sm text-gray-400 dark:text-gray-500">
+          {empty ?? 'データがありません'}
+        </p>
       )}
     </section>
   );

components/project/ProjectCard.tsx

@@ -11,27 +11,30 @@ const STATUS_COLORS: Record<string, string> = {
   active: 'bg-green-100 text-green-800',
   on_hold: 'bg-yellow-100 text-yellow-800',
   completed: 'bg-blue-100 text-blue-800',
-  archived: 'bg-gray-200 text-gray-700',
+  archived: 'bg-gray-200 dark:bg-gray-700 text-gray-700 dark:text-gray-200',
 };
 
 export function ProjectCard({ project }: { project: Project }) {
   return (
     <a
       href={`/projects/${project.id}`}
-      className="block rounded-lg border bg-white p-4 shadow-sm transition hover:shadow-md"
+      className="block rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm transition hover:shadow-md"
     >
       <div className="flex items-center justify-between">
-        <h3 className="font-semibold text-gray-800">{project.name}</h3>
+        <h3 className="font-semibold text-gray-800 dark:text-gray-100">
+          {project.name}
+        </h3>
         <span
           className={`rounded px-2 py-0.5 text-xs ${
-            STATUS_COLORS[project.status] ?? 'bg-gray-100 text-gray-700'
+            STATUS_COLORS[project.status] ??
+            'bg-gray-100 dark:bg-gray-700 text-gray-700 dark:text-gray-200'
           }`}
         >
           {STATUS_LABELS[project.status] ?? project.status}
         </span>
       </div>
       {project.description && (
-        <p className="mt-2 line-clamp-2 text-sm text-gray-600">
+        <p className="mt-2 line-clamp-2 text-sm text-gray-600 dark:text-gray-300">
           {project.description}
         </p>
       )}

components/project/ProjectSettingsForm.tsx

@@ -49,7 +49,7 @@ export function ProjectSettingsForm({
 
   if (!canManage) {
     return (
-      <p className="text-sm text-gray-500">
+      <p className="text-sm text-gray-500 dark:text-gray-400">
         プロジェクトの設定変更には管理者権限が必要です。
       </p>
     );

components/project/SearchForm.tsx

@@ -39,7 +39,7 @@ export function SearchForm({
   return (
     <form
       onSubmit={onSubmit}
-      className="flex flex-col gap-2 rounded-lg border bg-white p-4 shadow-sm sm:flex-row"
+      className="flex flex-col gap-2 rounded-lg border bg-white dark:bg-gray-800 p-4 shadow-sm sm:flex-row"
       data-testid="search-form"
     >
       <input

components/pwa/ServiceWorkerRegister.tsx

@@ -0,0 +1,27 @@
+'use client';
+
+import { useEffect } from 'react';
+
+/**
+ * Service Worker を登録する(本番環境のみ)。
+ * 開発環境では Next.js の HMR とSWキャッシュが衝突するため登録しない。
+ * 登録失敗はPWAがプログレッシブ拡張であるため無視する。
+ */
+export function ServiceWorkerRegister() {
+  useEffect(() => {
+    if (process.env.NODE_ENV !== 'production') return;
+    if (typeof window === 'undefined' || !('serviceWorker' in navigator)) {
+      return;
+    }
+    const register = () => {
+      navigator.serviceWorker.register('/sw.js').catch(() => undefined);
+    };
+    if (document.readyState === 'complete') {
+      register();
+    } else {
+      window.addEventListener('load', register, { once: true });
+    }
+  }, []);
+
+  return null;
+}

components/todo/KanbanBoard.tsx

@@ -1,25 +1,38 @@
 'use client';
 
-import { useCallback, useState, type DragEvent } from 'react';
+import { useCallback, useRef, useState, type DragEvent } from 'react';
 import type { TodoColumn, TodoItem } from '@/lib/types';
+import type { ProjectMemberWithUser } from '@/repositories/ProjectMemberRepository';
+import { TodoDialog } from '@/components/todo/TodoDialog';
 
 const PRIORITY_COLORS: Record<string, string> = {
   high: 'bg-red-100 text-red-700',
   normal: 'bg-yellow-100 text-yellow-700',
-  low: 'bg-gray-100 text-gray-600',
+  low: 'bg-gray-100 dark:bg-gray-700 text-gray-600 dark:text-gray-300',
 };
 
+/** 同一 orderIndex は id で安定ソート(createdAt 同着対策) */
+function byOrder(a: TodoItem, b: TodoItem): number {
+  return a.orderIndex - b.orderIndex || a.id - b.id;
+}
+
 export function KanbanBoard({
   projectId,
   columns,
   initialItems,
+  members,
 }: {
   projectId: number;
   columns: TodoColumn[];
   initialItems: TodoItem[];
+  members: ProjectMemberWithUser[];
 }) {
   const [items, setItems] = useState<TodoItem[]>(initialItems);
   const [draggingId, setDraggingId] = useState<number | null>(null);
+  const [selectedItem, setSelectedItem] = useState<TodoItem | null>(null);
+  const [error, setError] = useState<string | null>(null);
+  // ドラッグ直後の誤クリック(ダイアログを開く)を抑制するためのタイムスタンプ
+  const lastDragEndAtRef = useRef(0);
 
   const reload = useCallback(async () => {
     const res = await fetch(`/api/projects/${projectId}/todos/items`);
@@ -35,25 +48,84 @@ export function KanbanBoard({
     e.dataTransfer.setData('text/plain', String(itemId));
   }
 
+  function applyReorder(
+    prev: TodoItem[],
+    destColumnId: number,
+    newOrderIds: number[]
+  ): TodoItem[] {
+    const order = new Map(newOrderIds.map((id, idx) => [id, idx]));
+    return prev.map((i) =>
+      order.has(i.id)
+        ? { ...i, columnId: destColumnId, orderIndex: order.get(i.id)! }
+        : i
+    );
+  }
+
+  function columnItemIds(columnId: number, excludeId?: number): number[] {
+    return items
+      .filter((i) => i.columnId === columnId && i.id !== excludeId)
+      .sort((a, b) => a.orderIndex - b.orderIndex || a.id - b.id)
+      .map((i) => i.id);
+  }
+
+  async function persistReorder(
+    destColumnId: number,
+    newOrderIds: number[]
+  ): Promise<void> {
+    setItems((prev) => applyReorder(prev, destColumnId, newOrderIds));
+    setError(null);
+    try {
+      const res = await fetch(
+        `/api/projects/${projectId}/todos/items/reorder`,
+        {
+          method: 'POST',
+          headers: { 'Content-Type': 'application/json' },
+          body: JSON.stringify({
+            columnId: destColumnId,
+            itemIds: newOrderIds,
+          }),
+        }
+      );
+      if (!res.ok) {
+        setError('並べ替えに失敗しました');
+      }
+    } catch {
+      setError('並べ替えに失敗しました');
+    } finally {
+      await reload();
+    }
+    setDraggingId(null);
+  }
+
+  // カラムの空き領域へのドロップ = 末尾に追加
   function onDrop(e: DragEvent<HTMLElement>, column: TodoColumn) {
     e.preventDefault();
     const itemId = Number(e.dataTransfer.getData('text/plain'));
-    if (!itemId) return;
-    const item = items.find((i) => i.id === itemId);
-    if (!item || item.columnId === column.id) {
+    if (!itemId) {
       setDraggingId(null);
       return;
     }
-    // 楽観的にローカル更新したあとAPIで移動
-    setItems((prev) =>
-      prev.map((i) => (i.id === itemId ? { ...i, columnId: column.id } : i))
-    );
-    fetch(`/api/projects/${projectId}/todos/items/${itemId}`, {
-      method: 'PATCH',
-      headers: { 'Content-Type': 'application/json' },
-      body: JSON.stringify({ columnId: column.id, orderIndex: 0 }),
-    }).then(() => reload());
-    setDraggingId(null);
+    const newOrderIds = [...columnItemIds(column.id, itemId), itemId];
+    void persistReorder(column.id, newOrderIds);
+  }
+
+  // カード上へのドロップ = ポインタ位置で前後に挿入
+  function dropOnItem(e: DragEvent<HTMLElement>, target: TodoItem) {
+    e.preventDefault();
+    e.stopPropagation();
+    const itemId = Number(e.dataTransfer.getData('text/plain'));
+    if (!itemId || itemId === target.id) {
+      setDraggingId(null);
+      return;
+    }
+    const rect = e.currentTarget.getBoundingClientRect();
+    const before = e.clientY - rect.top < rect.height / 2;
+    const ordered = columnItemIds(target.columnId, itemId);
+    const insertAt = before
+      ? ordered.indexOf(target.id)
+      : ordered.indexOf(target.id) + 1;
+    ordered.splice(insertAt, 0, itemId);
+    void persistReorder(target.columnId, ordered);
   }
 
   async function addTask(columnId: number, title: string) {
@@ -75,65 +147,142 @@ export function KanbanBoard({
   }
 
   return (
-    <div className="flex gap-4 overflow-x-auto pb-4" data-testid="kanban-board">
-      {columns.map((column) => {
-        const colItems = items.filter((i) => i.columnId === column.id);
-        return (
-          <section
-            key={column.id}
-            className="w-64 shrink-0 rounded-lg bg-gray-100 p-3"
-            onDragOver={(e) => e.preventDefault()}
-            onDrop={(e) => onDrop(e, column)}
-            data-testid={`kanban-column-${column.id}`}
-            data-column-id={column.id}
-          >
-            <h2 className="mb-2 text-sm font-semibold text-gray-700">
-              {column.name} ({colItems.length})
-            </h2>
-            <ul className="space-y-2">
-              {colItems.map((item) => (
-                <li
-                  key={item.id}
-                  draggable
-                  onDragStart={(e) => onDragStart(e, item.id)}
-                  className={`cursor-grab rounded border bg-white p-2 shadow-sm ${
-                    draggingId === item.id ? 'opacity-50' : ''
-                  } ${item.completedAt ? 'opacity-60 line-through' : ''}`}
-                  data-testid={`todo-card-${item.id}`}
-                >
-                  <div className="flex items-start justify-between gap-2">
-                    <span className="text-sm">{item.title}</span>
-                    <button
-                      type="button"
-                      onClick={() => toggleComplete(item.id)}
-                      className="text-xs text-blue-600 hover:underline"
-                      data-testid={`todo-complete-${item.id}`}
+    <>
+      {error && (
+        <p
+          className="mb-2 text-sm text-red-600"
+          role="alert"
+          data-testid="kanban-error"
+        >
+          {error}
+        </p>
+      )}
+      <div
+        className="flex gap-4 overflow-x-auto pb-4"
+        data-testid="kanban-board"
+      >
+        {columns.map((column) => {
+          const colItems = items
+            .filter((i) => i.columnId === column.id)
+            .sort(byOrder);
+          return (
+            <section
+              key={column.id}
+              className="w-64 shrink-0 rounded-lg bg-gray-100 dark:bg-gray-700 p-3"
+              onDragOver={(e) => e.preventDefault()}
+              onDrop={(e) => onDrop(e, column)}
+              data-testid={`kanban-column-${column.id}`}
+              data-column-id={column.id}
+            >
+              <h2 className="mb-2 text-sm font-semibold text-gray-700 dark:text-gray-200">
+                {column.name} ({colItems.length})
+              </h2>
+              <ul className="space-y-2">
+                {colItems.map((item) => {
+                  const tags = item.tags
+                    ?.split(',')
+                    .map((t) => t.trim())
+                    .filter(Boolean);
+                  const assignee = members.find(
+                    (m) => m.user.id === item.assigneeId
+                  );
+                  return (
+                    <li
+                      key={item.id}
+                      draggable
+                      onDragStart={(e) => onDragStart(e, item.id)}
+                      onDragEnd={() => {
+                        lastDragEndAtRef.current = Date.now();
+                        setDraggingId(null);
+                      }}
+                      onDragOver={(e) => e.preventDefault()}
+                      onDrop={(e) => dropOnItem(e, item)}
+                      onClick={() => {
+                        // ドラッグ直後の誤クリックでダイアログが開かないようにする
+                        if (Date.now() - lastDragEndAtRef.current < 300) return;
+                        setSelectedItem(item);
+                      }}
+                      className={`cursor-grab rounded border bg-white dark:bg-gray-800 p-2 shadow-sm ${
+                        draggingId === item.id ? 'opacity-50' : ''
+                      } ${item.completedAt ? 'opacity-60 line-through' : ''}`}
+                      data-testid={`todo-card-${item.id}`}
                     >
-                      {item.completedAt ? '戻す' : '完了'}
-                    </button>
-                  </div>
-                  <div className="mt-1 flex gap-1">
-                    <span
-                      className={`rounded px-1.5 py-0.5 text-xs ${
-                        PRIORITY_COLORS[item.priority] ?? PRIORITY_COLORS.normal
-                      }`}
-                    >
-                      {item.priority}
-                    </span>
-                    {item.dueDate && (
-                      <span className="text-xs text-gray-500">
-                        期限: {item.dueDate}
-                      </span>
-                    )}
-                  </div>
-                </li>
-              ))}
-            </ul>
-            <NewTaskInput onAdd={(title) => addTask(column.id, title)} />
-          </section>
-        );
-      })}
-    </div>
+                      <div className="flex items-start justify-between gap-2">
+                        <span
+                          className="text-sm hover:text-blue-600 hover:underline"
+                          data-testid={`todo-open-${item.id}`}
+                        >
+                          {item.title}
+                        </span>
+                        <button
+                          type="button"
+                          onClick={(e) => {
+                            e.stopPropagation();
+                            toggleComplete(item.id);
+                          }}
+                          className="text-xs text-blue-600 hover:underline"
+                          data-testid={`todo-complete-${item.id}`}
+                        >
+                          {item.completedAt ? '戻す' : '完了'}
+                        </button>
+                      </div>
+                      <div className="mt-1 flex flex-wrap items-center gap-1">
+                        <span
+                          className={`rounded px-1.5 py-0.5 text-xs ${
+                            PRIORITY_COLORS[item.priority] ??
+                            PRIORITY_COLORS.normal
+                          }`}
+                        >
+                          {item.priority}
+                        </span>
+                        {item.dueDate && (
+                          <span className="text-xs text-gray-500 dark:text-gray-400">
+                            期限: {item.dueDate}
+                          </span>
+                        )}
+                        {item.startDate && (
+                          <span className="text-xs text-gray-400 dark:text-gray-500">
+                            開始: {item.startDate}
+                          </span>
+                        )}
+                        {assignee && (
+                          <span className="text-xs text-gray-500 dark:text-gray-400">
+                            @{assignee.user.name}
+                          </span>
+                        )}
+                      </div>
+                      {tags && tags.length > 0 && (
+                        <div className="mt-1 flex flex-wrap gap-1">
+                          {tags.map((t) => (
+                            <span
+                              key={t}
+                              className="rounded bg-gray-100 dark:bg-gray-700 px-1.5 py-0.5 text-[10px] text-gray-600 dark:text-gray-300"
+                            >
+                              {t}
+                            </span>
+                          ))}
+                        </div>
+                      )}
+                    </li>
+                  );
+                })}
+              </ul>
+              <NewTaskInput onAdd={(title) => addTask(column.id, title)} />
+            </section>
+          );
+        })}
+
+        {selectedItem && (
+          <TodoDialog
+            projectId={projectId}
+            item={selectedItem}
+            members={members}
+            onClose={() => setSelectedItem(null)}
+            onSaved={reload}
+          />
+        )}
+      </div>
+    </>
   );
 }
 

components/todo/TodoDialog.tsx

@@ -0,0 +1,317 @@
+'use client';
+
+import { useEffect, useRef, useState } from 'react';
+import type { AttachmentView, TodoItem, TodoPriority } from '@/lib/types';
+import type { ProjectMemberWithUser } from '@/repositories/ProjectMemberRepository';
+import { AttachmentList } from '@/components/files/AttachmentList';
+import {
+  AttachmentPicker,
+  type AttachmentPickerHandle,
+} from '@/components/files/AttachmentPicker';
+
+const PRIORITIES: TodoPriority[] = ['low', 'normal', 'high'];
+
+function parseTags(tags: string | null): string[] {
+  if (!tags) return [];
+  return tags
+    .split(',')
+    .map((t) => t.trim())
+    .filter((t) => t.length > 0);
+}
+
+/**
+ * ToDo編集/詳細ダイアログ。
+ * カードクリックで開き、タイトル/説明/担当/優先度/開始日/期限/タグ/添付を
+ * 編集・閲覧できる。完了日(完了時刻)・作成/更新日時は読み取り専用で表示。
+ */
+export function TodoDialog({
+  projectId,
+  item,
+  members,
+  onClose,
+  onSaved,
+}: {
+  projectId: number;
+  item: TodoItem;
+  members: ProjectMemberWithUser[];
+  onClose: () => void;
+  onSaved: () => void | Promise<void>;
+}) {
+  const [title, setTitle] = useState(item.title);
+  const [description, setDescription] = useState(item.description ?? '');
+  const [assigneeId, setAssigneeId] = useState<string>(
+    item.assigneeId ? String(item.assigneeId) : ''
+  );
+  const [priority, setPriority] = useState<TodoPriority>(item.priority);
+  const [startDate, setStartDate] = useState(item.startDate ?? '');
+  const [dueDate, setDueDate] = useState(item.dueDate ?? '');
+  const [tags, setTags] = useState(item.tags ?? '');
+  const [attachments, setAttachments] = useState<AttachmentView[]>([]);
+  const [current, setCurrent] = useState<TodoItem>(item);
+  const [loading, setLoading] = useState(true);
+  const [saving, setSaving] = useState(false);
+  const [pickerLoading, setPickerLoading] = useState(false);
+  const [error, setError] = useState<string | null>(null);
+  const pickerRef = useRef<AttachmentPickerHandle>(null);
+
+  // 開封時に最新のアイテム+添付を取得
+  useEffect(() => {
+    let alive = true;
+    setLoading(true);
+    fetch(`/api/projects/${projectId}/todos/items/${item.id}`)
+      .then((res) => (res.ok ? res.json() : null))
+      .then((data) => {
+        if (!alive || !data) return;
+        const fetched = data.item as TodoItem;
+        setTitle(fetched.title);
+        setDescription(fetched.description ?? '');
+        setAssigneeId(fetched.assigneeId ? String(fetched.assigneeId) : '');
+        setPriority(fetched.priority);
+        setStartDate(fetched.startDate ?? '');
+        setDueDate(fetched.dueDate ?? '');
+        setTags(fetched.tags ?? '');
+        setAttachments((data.attachments as AttachmentView[]) ?? []);
+        setCurrent(fetched);
+      })
+      .catch(() => undefined)
+      .finally(() => alive && setLoading(false));
+    return () => {
+      alive = false;
+    };
+  }, [projectId, item.id]);
+
+  useEffect(() => {
+    function onKey(e: KeyboardEvent) {
+      if (e.key === 'Escape') onClose();
+    }
+    window.addEventListener('keydown', onKey);
+    return () => window.removeEventListener('keydown', onKey);
+  }, [onClose]);
+
+  async function onSave() {
+    setSaving(true);
+    setError(null);
+    const fileIds = pickerRef.current?.getFileIds() ?? [];
+    const res = await fetch(
+      `/api/projects/${projectId}/todos/items/${item.id}`,
+      {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify({
+          title,
+          description,
+          assigneeId: assigneeId ? Number(assigneeId) : null,
+          priority,
+          startDate: startDate || null,
+          dueDate: dueDate || null,
+          tags: tags || null,
+          fileIds,
+        }),
+      }
+    );
+    setSaving(false);
+    if (res.ok) {
+      pickerRef.current?.clear();
+      await onSaved();
+      onClose();
+    } else {
+      const b = (await res.json().catch(() => null)) as {
+        error?: { message?: string };
+      } | null;
+      setError(b?.error?.message ?? '保存に失敗しました');
+    }
+  }
+
+  const tagList = parseTags(tags);
+
+  return (
+    <div
+      className="fixed inset-0 z-50 flex items-start justify-center bg-black/40 p-4"
+      onClick={onClose}
+      data-testid="todo-dialog-backdrop"
+    >
+      <div
+        className="mt-8 w-full max-w-xl rounded-lg bg-white dark:bg-gray-800 shadow-xl"
+        onClick={(e) => e.stopPropagation()}
+        role="dialog"
+        aria-modal="true"
+        aria-label={`ToDo ${item.title} の編集`}
+        data-testid="todo-dialog"
+      >
+        <div className="flex items-center justify-between border-b p-4">
+          <h2 className="text-lg font-bold text-gray-800 dark:text-gray-100">
+            ToDoの編集
+          </h2>
+          <button
+            type="button"
+            onClick={onClose}
+            className="rounded p-1 text-gray-400 dark:text-gray-500 hover:bg-gray-100 dark:hover:bg-gray-700 hover:text-gray-600"
+            aria-label="閉じる"
+            data-testid="todo-dialog-close"
+          >
+            ×
+          </button>
+        </div>
+
+        {loading ? (
+          <p className="p-6 text-sm text-gray-400 dark:text-gray-500">
+            読み込み中...
+          </p>
+        ) : (
+          <div className="max-h-[70vh] space-y-3 overflow-y-auto p-4">
+            <div>
+              <label className="block text-sm font-medium">タイトル</label>
+              <input
+                type="text"
+                value={title}
+                onChange={(e) => setTitle(e.target.value)}
+                className="mt-1 w-full rounded border px-3 py-2"
+                data-testid="todo-title"
+              />
+            </div>
+            <div>
+              <label className="block text-sm font-medium">説明</label>
+              <textarea
+                value={description}
+                onChange={(e) => setDescription(e.target.value)}
+                className="mt-1 min-h-[80px] w-full rounded border px-3 py-2"
+                data-testid="todo-description"
+              />
+            </div>
+            <div className="grid grid-cols-2 gap-3">
+              <div>
+                <label className="block text-sm font-medium">担当者</label>
+                <select
+                  value={assigneeId}
+                  onChange={(e) => setAssigneeId(e.target.value)}
+                  className="mt-1 w-full rounded border px-3 py-2"
+                  data-testid="todo-assignee"
+                >
+                  <option value="">未割当</option>
+                  {members.map((m) => (
+                    <option key={m.user.id} value={String(m.user.id)}>
+                      {m.user.name}
+                    </option>
+                  ))}
+                </select>
+              </div>
+              <div>
+                <label className="block text-sm font-medium">優先度</label>
+                <select
+                  value={priority}
+                  onChange={(e) => setPriority(e.target.value as TodoPriority)}
+                  className="mt-1 w-full rounded border px-3 py-2"
+                  data-testid="todo-priority"
+                >
+                  {PRIORITIES.map((p) => (
+                    <option key={p} value={p}>
+                      {p}
+                    </option>
+                  ))}
+                </select>
+              </div>
+            </div>
+            <div className="grid grid-cols-2 gap-3">
+              <div>
+                <label className="block text-sm font-medium">開始日</label>
+                <input
+                  type="date"
+                  value={startDate}
+                  onChange={(e) => setStartDate(e.target.value)}
+                  className="mt-1 w-full rounded border px-3 py-2"
+                  data-testid="todo-start-date"
+                />
+              </div>
+              <div>
+                <label className="block text-sm font-medium">
+                  期限 (deadline)
+                </label>
+                <input
+                  type="date"
+                  value={dueDate}
+                  onChange={(e) => setDueDate(e.target.value)}
+                  className="mt-1 w-full rounded border px-3 py-2"
+                  data-testid="todo-due-date"
+                />
+              </div>
+            </div>
+            <div>
+              <label className="block text-sm font-medium">
+                タグ (カンマ区切り)
+              </label>
+              <input
+                type="text"
+                value={tags}
+                onChange={(e) => setTags(e.target.value)}
+                placeholder="frontend, urgent"
+                className="mt-1 w-full rounded border px-3 py-2"
+                data-testid="todo-tags"
+              />
+              {tagList.length > 0 && (
+                <div className="mt-1 flex flex-wrap gap-1">
+                  {tagList.map((t) => (
+                    <span
+                      key={t}
+                      className="rounded bg-gray-100 dark:bg-gray-700 px-2 py-0.5 text-xs text-gray-600 dark:text-gray-300"
+                    >
+                      {t}
+                    </span>
+                  ))}
+                </div>
+              )}
+            </div>
+
+            <div>
+              <p className="mb-1 text-sm font-medium">添付ファイル</p>
+              {attachments.length > 0 ? (
+                <AttachmentList attachments={attachments} />
+              ) : (
+                <p className="text-xs text-gray-400 dark:text-gray-500">
+                  添付なし
+                </p>
+              )}
+              <div className="mt-2">
+                <AttachmentPicker
+                  ref={pickerRef}
+                  projectId={projectId}
+                  onLoadingChange={setPickerLoading}
+                />
+              </div>
+            </div>
+
+            <div className="space-y-1 border-t pt-3 text-xs text-gray-500 dark:text-gray-400">
+              <p>完了日時: {current.completedAt ?? '未完了'}</p>
+              <p>作成: {current.createdAt}</p>
+              <p>更新: {current.updatedAt}</p>
+            </div>
+
+            {error && (
+              <p className="text-sm text-red-600" role="alert">
+                {error}
+              </p>
+            )}
+          </div>
+        )}
+
+        <div className="flex justify-end gap-2 border-t p-4">
+          <button
+            type="button"
+            onClick={onClose}
+            className="rounded border px-4 py-2 text-sm text-gray-600 dark:text-gray-300 hover:bg-gray-100 dark:hover:bg-gray-700"
+          >
+            キャンセル
+          </button>
+          <button
+            type="button"
+            onClick={onSave}
+            disabled={saving || pickerLoading || loading}
+            className="rounded bg-blue-600 px-4 py-2 text-sm font-medium text-white hover:bg-blue-700 disabled:opacity-50"
+            data-testid="todo-save"
+          >
+            {saving ? '保存中...' : '保存'}
+          </button>
+        </div>
+      </div>
+    </div>
+  );
+}

docs/functional-design.md

@@ -84,11 +84,15 @@ interface User {
   avatarUrl: string | null;     // アイコン画像URL
   role: UserRole;               // 'system_admin' | 'project_admin' | 'member' | 'guest'
   status: UserStatus;           // 'active' | 'inactive'
+  theme: Theme;                 // 'dark' | 'light' (既定 dark)
+  locale: Locale;               // 'en' | 'ja' (既定 en)
   createdAt: string;            // ISO8601
   updatedAt: string;            // ISO8601
 }
 type UserRole = 'system_admin' | 'project_admin' | 'member' | 'guest';
 type UserStatus = 'active' | 'inactive';
+type Theme = 'dark' | 'light';
+type Locale = 'en' | 'ja';
 ```
 
 **制約**: emailは一意。passwordHashは平文保存しない。status='inactive'はログイン不可。
@@ -200,6 +204,7 @@ interface TodoItem {
   completedAt: string | null;
   orderIndex: number;
   milestoneId: number | null;   // FK milestones.id
+  tags: string | null;          // カンマ区切りのタグ(project_notes.tags と同じ方式)
   createdAt: string;
   updatedAt: string;
   deletedAt: string | null;
@@ -219,9 +224,31 @@ interface FileAsset {
   mimeType: string;             // MIMEタイプ（アップロード時チェック）
   size: number;                 // バイト数
   path: string;                 // ローカルパス（uploads/...）
+  source: FileAssetSource;      // 'library'(Files一覧公開) | 'attachment'(添付専用)
   createdAt: string;
   deletedAt: string | null;
 }
+type FileAssetSource = 'library' | 'attachment';
+```
+
+### attachments
+
+```typescript
+// file_assets とチャット/掲示板/ToDo を多対多で紐付ける
+interface Attachment {
+  id: number;
+  projectId: number;            // FK projects.id ON DELETE CASCADE
+  fileId: number;               // FK file_assets.id
+  targetType: AttachmentTargetType;
+  targetId: number;             // targetType に応じた chat_message/board_thread/board_comment/todo_item の id
+  createdAt: string;
+  deletedAt: string | null;
+}
+type AttachmentTargetType =
+  | 'chat_message'
+  | 'board_thread'
+  | 'board_comment'
+  | 'todo_item';
 ```
 
 ### project_notes
@@ -410,6 +437,7 @@ erDiagram
         integer assignee_id FK
         integer milestone_id FK
         text due_date
+        text tags
     }
     meetings {
         integer id PK

docs/repository-structure.md

@@ -235,7 +235,7 @@ components/
 ├── project/             # ProjectCard, DashboardWidget
 ├── board/               # ThreadList, ThreadForm, CommentList
 ├── chat/                # ChatWindow, MessageInput, MessageList
-├── todo/                # KanbanBoard, KanbanColumn, TodoCard
+├── todo/                # KanbanBoard, TodoDialog
 ├── files/               # FileList, Uploader, Lightbox, AttachmentList, AttachmentPicker
 ├── calendar/            # CalendarView, MonthView, WeekView, DayView, EventDetailDialog, CalendarEventForm
 ├── meetings/            # MeetingForm, ConflictWarning

eslint.config.js

@@ -28,6 +28,8 @@ export default tseslint.config(
       'playwright-report/**',
       'test-results/**',
       'next-env.d.ts',
+      'scripts/**/*.mjs',
+      'public/**',
     ],
   }
 );

lib/api/services.ts

@@ -98,12 +98,19 @@ export function createChatService(): ChatService {
 
 export function createTodoService(): TodoService {
   const db = getDb();
+  const memberRepo = new ProjectMemberRepository(db);
   return new TodoService(
     new TodoRepository(db),
-    new ProjectMemberRepository(db),
+    memberRepo,
     new NotificationService(new NotificationRepository(db)),
     new ActivityLogService(new ActivityLogRepository(db)),
-    getSseHub()
+    getSseHub(),
+    new AttachmentService(
+      new AttachmentRepository(db),
+      new FileRepository(db),
+      memberRepo
+    ),
+    db
   );
 }
 

lib/auth/getCurrentUser.ts

@@ -16,6 +16,8 @@ export function toPublicUser(user: User): PublicUser {
     avatarUrl: user.avatarUrl,
     role: user.role,
     status: user.status,
+    theme: user.theme,
+    locale: user.locale,
     createdAt: user.createdAt,
     updatedAt: user.updatedAt,
   };

lib/db/migrations/003_todo_tags.sql

@@ -0,0 +1,4 @@
+-- 003_todo_tags.sql
+-- ToDoアイテムにタグ列を追加(カンマ区切り、project_notes.tags と同じ方式)。
+
+ALTER TABLE todo_items ADD COLUMN tags TEXT;

lib/db/migrations/004_user_prefs.sql

@@ -0,0 +1,5 @@
+-- 004_user_prefs.sql
+-- ユーザーごとのテーマ(dark/light)と言語(en/ja)設定を追加。
+
+ALTER TABLE users ADD COLUMN theme TEXT NOT NULL DEFAULT 'dark';
+ALTER TABLE users ADD COLUMN locale TEXT NOT NULL DEFAULT 'en';

lib/i18n/I18nProvider.tsx

@@ -0,0 +1,99 @@
+'use client';
+
+import {
+  createContext,
+  useCallback,
+  useContext,
+  useMemo,
+  useState,
+  type ReactNode,
+} from 'react';
+import { useRouter } from 'next/navigation';
+import { dictionary, type MessageKey } from '@/lib/i18n/dictionary';
+import { PREF_MAX_AGE } from '@/lib/i18n/constants';
+import type { Locale, Theme } from '@/lib/types';
+
+interface I18nContextValue {
+  locale: Locale;
+  theme: Theme;
+  t: (key: MessageKey) => string;
+  setLocale: (locale: Locale) => void;
+  setTheme: (theme: Theme) => Promise<void>;
+}
+
+const I18nContext = createContext<I18nContextValue | null>(null);
+
+/**
+ * 言語とテーマのクライアント状態を提供するコンテキスト。
+ * - locale: 辞書の切り替え(t)と <html lang> の更新
+ * - setLocale/setTheme: Cookie を即時設定し /api/users/me で永続化、router.refresh でSSR再描画
+ */
+export function I18nProvider({
+  initialLocale,
+  initialTheme,
+  children,
+}: {
+  initialLocale: Locale;
+  initialTheme: Theme;
+  children: ReactNode;
+}) {
+  const router = useRouter();
+  const [locale, setLocaleState] = useState<Locale>(initialLocale);
+  const [theme, setThemeState] = useState<Theme>(initialTheme);
+
+  const t = useCallback(
+    (key: MessageKey) => dictionary[locale][key] ?? dictionary.en[key] ?? key,
+    [locale]
+  );
+
+  const persist = useCallback(async (body: Record<string, unknown>) => {
+    try {
+      await fetch('/api/users/me', {
+        method: 'PATCH',
+        headers: { 'Content-Type': 'application/json' },
+        body: JSON.stringify(body),
+      });
+    } catch (error) {
+      // 永続化失敗時もローカルCookieで動作継続するが、ログは残す
+      console.warn('Failed to persist user prefs:', error);
+    }
+  }, []);
+
+  const setLocale = useCallback(
+    (next: Locale) => {
+      setLocaleState(next);
+      document.cookie = `locale=${next}; path=/; max-age=${PREF_MAX_AGE}; samesite=lax`;
+      void persist({ locale: next });
+      router.refresh();
+    },
+    [persist, router]
+  );
+
+  const setTheme = useCallback(
+    async (next: Theme) => {
+      setThemeState(next);
+      const root = document.documentElement;
+      if (next === 'dark') root.classList.add('dark');
+      else root.classList.remove('dark');
+      root.style.colorScheme = next;
+      document.cookie = `theme=${next}; path=/; max-age=${PREF_MAX_AGE}; samesite=lax`;
+      await persist({ theme: next });
+    },
+    [persist]
+  );
+
+  const value = useMemo<I18nContextValue>(
+    () => ({ locale, theme, t, setLocale, setTheme }),
+    [locale, theme, t, setLocale, setTheme]
+  );
+
+  return <I18nContext.Provider value={value}>{children}</I18nContext.Provider>;
+}
+
+export function useI18n(): I18nContextValue {
+  const ctx = useContext(I18nContext);
+  if (!ctx) {
+    throw new Error('useI18n must be used within I18nProvider');
+  }
+  return ctx;
+}

lib/i18n/constants.ts

@@ -0,0 +1,10 @@
+import type { Locale, Theme } from '@/lib/types';
+
+/** テーマ/言語のプリフ Cookie の有効期限(1年)。 */
+export const PREF_MAX_AGE = 60 * 60 * 24 * 365;
+
+/** 許容されるテーマ。 */
+export const VALID_THEMES: Theme[] = ['dark', 'light'];
+
+/** 許容される言語。 */
+export const VALID_LOCALES: Locale[] = ['en', 'ja'];

lib/i18n/dictionary.ts

@@ -0,0 +1,172 @@
+import type { Locale } from '@/lib/types';
+
+/**
+ * 多言語辞書。en/ja の両方に同じキーを定義する。
+ * 共通クロム(ヘッダー/ナビ)、認証、プロフィール/設定、ページタイトル、
+ * 共通アクションラベルをカバーする。機能画面の本文は漸次追加する。
+ */
+const en = {
+  'app.name': 'Groupware',
+  'nav.dashboard': 'Dashboard',
+  'nav.overview': 'Overview',
+  'nav.board': 'Board',
+  'nav.notes': 'Notes',
+  'nav.chat': 'Chat',
+  'nav.todos': 'ToDo',
+  'nav.files': 'Files',
+  'nav.calendar': 'Calendar',
+  'nav.milestones': 'Milestones',
+  'nav.meetings': 'Meetings',
+  'nav.search': 'Search',
+  'nav.members': 'Members',
+  'nav.activity': 'Activity',
+  'nav.settings': 'Settings',
+  'header.logout': 'Logout',
+  'common.save': 'Save',
+  'common.cancel': 'Cancel',
+  'common.create': 'Create',
+  'common.delete': 'Delete',
+  'common.submit': 'Submit',
+  'common.loading': 'Loading...',
+  'common.back': 'Back',
+  'common.edit': 'Edit',
+  'theme.dark': 'Dark',
+  'theme.light': 'Light',
+  'language.english': 'English',
+  'language.japanese': '日本語',
+  'auth.login': 'Login',
+  'auth.register': 'Register',
+  'auth.displayName': 'Display name',
+  'auth.email': 'Email',
+  'auth.password': 'Password',
+  'auth.registerHere': 'New here? Register',
+  'auth.registerButton': 'Register',
+  'auth.loginButton': 'Login',
+  'auth.backToLogin': 'Back to login',
+  'auth.processing': 'Processing...',
+  'auth.failed': 'Operation failed',
+  'auth.projectName': 'Project name',
+  'auth.newProject': 'New project',
+  'project.description': 'Description (optional)',
+  'project.creating': 'Creating...',
+  'project.createFailed': 'Failed to create project',
+  'profile.title': 'Profile',
+  'profile.displayName': 'Display name',
+  'profile.email': 'Email',
+  'profile.avatarUrl': 'Avatar image URL',
+  'profile.saved': 'Profile updated',
+  'profile.backToDashboard': 'Back to dashboard',
+  'profile.role': 'Role',
+  'profile.theme': 'Theme',
+  'profile.language': 'Language',
+  'page.dashboard': 'Dashboard',
+  'page.board': 'Board',
+  'page.notes': 'Notes',
+  'page.chat': 'Chat',
+  'page.todos': 'ToDo / Kanban',
+  'page.files': 'Files',
+  'page.calendar': 'Calendar',
+  'page.milestones': 'Milestones',
+  'page.meetings': 'Meetings',
+  'page.search': 'Search',
+  'page.members': 'Members',
+  'page.activity': 'Activity',
+  'page.settings': 'Settings',
+  'page.profile': 'Profile',
+  'page.login': 'Login',
+  'dash.projects': 'Joined projects',
+  'dash.unreadNotifications': 'Unread notifications',
+  'dash.incompleteTodos': 'Incomplete ToDo',
+  'dash.overdueTasks': 'Overdue tasks',
+  'dash.upcomingMeetings': 'Upcoming meetings',
+  'dash.recentActivity': 'Recent activity',
+  'dash.empty': 'None',
+  'dash.noUnread': 'No unread',
+  'dash.openNotifications': 'Open notifications',
+  'dash.due': 'Due',
+};
+
+const ja: typeof en = {
+  'app.name': 'シンプルグループウェア',
+  'nav.dashboard': 'ダッシュボード',
+  'nav.overview': '概要',
+  'nav.board': '掲示板',
+  'nav.notes': 'メモ',
+  'nav.chat': 'チャット',
+  'nav.todos': 'ToDo',
+  'nav.files': 'ファイル',
+  'nav.calendar': 'カレンダー',
+  'nav.milestones': 'マイルストーン',
+  'nav.meetings': 'ミーティング',
+  'nav.search': '検索',
+  'nav.members': 'メンバー',
+  'nav.activity': 'アクティビティ',
+  'nav.settings': '設定',
+  'header.logout': 'ログアウト',
+  'common.save': '保存',
+  'common.cancel': 'キャンセル',
+  'common.create': '作成',
+  'common.delete': '削除',
+  'common.submit': '送信',
+  'common.loading': '読み込み中...',
+  'common.back': '戻る',
+  'common.edit': '編集',
+  'theme.dark': 'ダーク',
+  'theme.light': 'ライト',
+  'language.english': 'English',
+  'language.japanese': '日本語',
+  'auth.login': 'ログイン',
+  'auth.register': '新規登録',
+  'auth.displayName': '表示名',
+  'auth.email': 'メールアドレス',
+  'auth.password': 'パスワード',
+  'auth.registerHere': '新規登録はこちら',
+  'auth.registerButton': '登録する',
+  'auth.loginButton': 'ログイン',
+  'auth.backToLogin': 'ログイン画面に戻る',
+  'auth.processing': '処理中...',
+  'auth.failed': '処理に失敗しました',
+  'auth.projectName': 'プロジェクト名',
+  'auth.newProject': '新規プロジェクト',
+  'project.description': '説明（任意）',
+  'project.creating': '作成中...',
+  'project.createFailed': 'プロジェクトの作成に失敗しました',
+  'profile.title': 'プロフィール',
+  'profile.displayName': '表示名',
+  'profile.email': 'メールアドレス',
+  'profile.avatarUrl': 'アイコン画像URL',
+  'profile.saved': 'プロフィールを更新しました',
+  'profile.backToDashboard': 'ダッシュボードへ',
+  'profile.role': 'ロール',
+  'profile.theme': 'テーマ',
+  'profile.language': '言語',
+  'page.dashboard': 'ダッシュボード',
+  'page.board': '掲示板',
+  'page.notes': 'メモ',
+  'page.chat': 'チャット',
+  'page.todos': 'ToDo / Kanban',
+  'page.files': 'ファイル',
+  'page.calendar': 'カレンダー',
+  'page.milestones': 'マイルストーン',
+  'page.meetings': 'ミーティング',
+  'page.search': '検索',
+  'page.members': 'メンバー',
+  'page.activity': 'アクティビティ',
+  'page.settings': '設定',
+  'page.profile': 'プロフィール',
+  'page.login': 'ログイン',
+  'dash.projects': '参加プロジェクト',
+  'dash.unreadNotifications': '未読通知',
+  'dash.incompleteTodos': '未完了ToDo',
+  'dash.overdueTasks': '期限切れタスク',
+  'dash.upcomingMeetings': '近日中のミーティング',
+  'dash.recentActivity': '最近のアクティビティ',
+  'dash.empty': 'ありません',
+  'dash.noUnread': '未読はありません',
+  'dash.openNotifications': '通知一覧を開く',
+  'dash.due': '期限',
+};
+
+export const dictionary: Record<Locale, typeof en> = { en, ja };
+
+export type MessageKey = keyof typeof en;

lib/i18n/server.ts

@@ -0,0 +1,20 @@
+import { cookies } from 'next/headers';
+import { dictionary, type MessageKey } from './dictionary';
+import type { Locale, Theme } from '@/lib/types';
+
+/** サーバー側で locale Cookie を読み解決する(既定 en)。 */
+export async function getLocale(): Promise<Locale> {
+  const c = await cookies();
+  return c.get('locale')?.value === 'ja' ? 'ja' : 'en';
+}
+
+/** サーバー側で theme Cookie を読み解決する(既定 dark)。 */
+export async function getTheme(): Promise<Theme> {
+  const c = await cookies();
+  return c.get('theme')?.value === 'light' ? 'light' : 'dark';
+}
+
+/** サーバー側で翻訳文字列を取得する。 */
+export function translate(key: MessageKey, locale: Locale): string {
+  return dictionary[locale][key] ?? dictionary.en[key] ?? key;
+}

lib/types/index.ts

@@ -8,6 +8,8 @@
 
 export type UserRole = 'system_admin' | 'project_admin' | 'member' | 'guest';
 export type UserStatus = 'active' | 'inactive';
+export type Theme = 'dark' | 'light';
+export type Locale = 'en' | 'ja';
 export type ProjectStatus = 'active' | 'on_hold' | 'completed' | 'archived';
 export type ProjectMemberRole = 'admin' | 'member' | 'guest';
 export type BoardCategory =
@@ -48,6 +50,8 @@ export interface User {
   avatarUrl: string | null;
   role: UserRole;
   status: UserStatus;
+  theme: Theme;
+  locale: Locale;
   createdAt: string;
   updatedAt: string;
 }
@@ -127,6 +131,7 @@ export interface TodoItem {
   completedAt: string | null;
   orderIndex: number;
   milestoneId: number | null;
+  tags: string | null;
   createdAt: string;
   updatedAt: string;
   deletedAt: string | null;
@@ -153,7 +158,8 @@ export type FileAssetSource = 'library' | 'attachment';
 export type AttachmentTargetType =
   | 'chat_message'
   | 'board_thread'
-  | 'board_comment';
+  | 'board_comment'
+  | 'todo_item';
 
 /** attachments エンティティ。 */
 export interface Attachment {

lib/validators/userValidator.ts

@@ -1,4 +1,6 @@
 import { ValidationError } from '@/lib/errors';
+import type { Locale, Theme } from '@/lib/types';
+import { VALID_LOCALES, VALID_THEMES } from '@/lib/i18n/constants';
 
 const EMAIL_RE = /^[^\s@]+@[^\s@]+\.[^\s@]+$/;
 const MAX_NAME_LENGTH = 100;
@@ -20,6 +22,8 @@ export interface ProfileUpdateInput {
   name?: string;
   email?: string;
   avatarUrl?: string;
+  theme?: Theme;
+  locale?: Locale;
 }
 
 export function validateRegister(input: RegisterInput): void {
@@ -41,7 +45,9 @@ export function validateProfileUpdate(input: ProfileUpdateInput): void {
   if (
     input.name === undefined &&
     input.email === undefined &&
-    input.avatarUrl === undefined
+    input.avatarUrl === undefined &&
+    input.theme === undefined &&
+    input.locale === undefined
   ) {
     throw new ValidationError('更新対象のフィールドを指定してください');
   }
@@ -56,6 +62,12 @@ export function validateProfileUpdate(input: ProfileUpdateInput): void {
       'avatarUrl'
     );
   }
+  if (input.theme !== undefined && !VALID_THEMES.includes(input.theme)) {
+    throw new ValidationError('無効なテーマです', 'theme');
+  }
+  if (input.locale !== undefined && !VALID_LOCALES.includes(input.locale)) {
+    throw new ValidationError('無効な言語です', 'locale');
+  }
 }
 
 function validateName(name: string): void {

middleware.ts

@@ -19,7 +19,7 @@ export function middleware(request: NextRequest) {
 
 export const config = {
   matcher: [
-    // /login, /api, _next 静的 assets, favicon を除外
-    '/((?!login|api|_next/static|_next/image|favicon.ico).*)',
+    // /login, /api, _next 静的 assets, favicon, PWA静的リソース(manifest/SW/icon) を除外
+    '/((?!login|api|_next/static|_next/image|favicon.ico|sw\\.js|manifest\\.webmanifest|icon\\.svg|icon-192\\.png|icon-512\\.png).*)',
   ],
 };

playwright.config.ts

@@ -12,6 +12,9 @@ export default defineConfig({
   use: {
     baseURL: 'http://localhost:3000',
     trace: 'on-first-retry',
+    // E2Eは既存の日本語アサーションを維持するため既定で ja ロケールを使用。
+    // (既定UIは en だが、テストは ja Cookie を与えて日本語表示を検証する)
+    storageState: 'tests/e2e/locale-ja.json',
   },
   projects: [
     {

public/icon.svg

@@ -0,0 +1,5 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 512 512" width="512" height="512" role="img" aria-label="Groupware">
+  <rect width="512" height="512" rx="96" fill="#2563eb"/>
+  <circle cx="256" cy="196" r="84" fill="#ffffff"/>
+  <path d="M128 432c0-70.7 57.3-128 128-128s128 57.3 128 128v24H128z" fill="#ffffff"/>
+</svg>

public/sw.js

@@ -0,0 +1,82 @@
+// Groupware service worker: app-shell precache + network-first navigations +
+// cache-first static assets for offline support and installability.
+const CACHE = 'ogw-v1';
+const PRECACHE_URLS = [
+  '/',
+  '/manifest.webmanifest',
+  '/icon.svg',
+  '/icon-192.png',
+  '/icon-512.png',
+];
+
+self.addEventListener('install', (event) => {
+  event.waitUntil(
+    (async () => {
+      const cache = await caches.open(CACHE);
+      // 一つでも欠けていても全体が失敗しないよう個別に追加
+      await Promise.allSettled(PRECACHE_URLS.map((u) => cache.add(u)));
+      await self.skipWaiting();
+    })()
+  );
+});
+
+self.addEventListener('activate', (event) => {
+  event.waitUntil(
+    (async () => {
+      const keys = await caches.keys();
+      await Promise.all(
+        keys.filter((k) => k !== CACHE).map((k) => caches.delete(k))
+      );
+      await self.clients.claim();
+    })()
+  );
+});
+
+self.addEventListener('fetch', (event) => {
+  const req = event.request;
+  if (req.method !== 'GET') return;
+
+  const url = new URL(req.url);
+  // クロスオリジンとAPIはキャッシュしない
+  if (url.origin !== self.location.origin || url.pathname.startsWith('/api')) {
+    return;
+  }
+
+  // ナビゲーション: ネットワーク優先(オフライン時はキャッシュ/"/"にフォールバック)
+  if (req.mode === 'navigate') {
+    event.respondWith(
+      (async () => {
+        try {
+          const res = await fetch(req);
+          // エラーや認証リダイレクトの結果をキャッシュしない
+          if (res.ok && res.type === 'basic') {
+            const cache = await caches.open(CACHE);
+            cache.put(req, res.clone());
+          }
+          return res;
+        } catch {
+          const cached = await caches.match(req);
+          return cached || (await caches.match('/')) || Response.error();
+        }
+      })()
+    );
+    return;
+  }
+
+  // 静的アセット: キャッシュ優先(stale-while-revalidate)
+  event.respondWith(
+    (async () => {
+      const cached = await caches.match(req);
+      const network = fetch(req)
+        .then((res) => {
+          if (res && res.status === 200 && res.type === 'basic') {
+            const cache = caches.open(CACHE);
+            cache.then((c) => c.put(req, res.clone()));
+          }
+          return res;
+        })
+        .catch(() => undefined);
+      return cached || (await network) || Response.error();
+    })()
+  );
+});

repositories/MilestoneRepository.ts

@@ -1,5 +1,10 @@
 import type { SqliteDatabase } from '@/lib/db/sqlite';
-import type { Milestone, MilestoneStatus, TodoItem } from '@/lib/types';
+import type {
+  Milestone,
+  MilestoneStatus,
+  TodoItem,
+  TodoPriority,
+} from '@/lib/types';
 
 interface MilestoneRow {
   id: number;
@@ -27,6 +32,7 @@ interface TodoItemRow {
   completed_at: string | null;
   order_index: number;
   milestone_id: number | null;
+  tags: string | null;
   created_at: string;
   updated_at: string;
   deleted_at: string | null;
@@ -55,12 +61,13 @@ function mapTodo(row: TodoItemRow): TodoItem {
     description: row.description,
     assigneeId: row.assignee_id,
     creatorId: row.creator_id,
-    priority: row.priority as never,
+    priority: row.priority as TodoPriority,
     startDate: row.start_date,
     dueDate: row.due_date,
     completedAt: row.completed_at,
     orderIndex: row.order_index,
     milestoneId: row.milestone_id,
+    tags: row.tags,
     createdAt: row.created_at,
     updatedAt: row.updated_at,
     deletedAt: row.deleted_at,

repositories/TodoRepository.ts

@@ -24,6 +24,7 @@ interface TodoItemRow {
   completed_at: string | null;
   order_index: number;
   milestone_id: number | null;
+  tags: string | null;
   created_at: string;
   updated_at: string;
   deleted_at: string | null;
@@ -55,6 +56,7 @@ function mapItem(row: TodoItemRow): TodoItem {
     completedAt: row.completed_at,
     orderIndex: row.order_index,
     milestoneId: row.milestone_id,
+    tags: row.tags,
     createdAt: row.created_at,
     updatedAt: row.updated_at,
     deletedAt: row.deleted_at,
@@ -75,7 +77,9 @@ export interface CreateItemInput {
   description?: string | null;
   assigneeId?: number | null;
   priority?: TodoPriority;
+  startDate?: string | null;
   dueDate?: string | null;
+  tags?: string | null;
   orderIndex: number;
 }
 
@@ -84,7 +88,9 @@ export interface UpdateItemInput {
   description?: string | null;
   assigneeId?: number | null;
   priority?: TodoPriority;
+  startDate?: string | null;
   dueDate?: string | null;
+  tags?: string | null;
   completedAt?: string | null;
   columnId?: number;
   orderIndex?: number;
@@ -193,8 +199,8 @@ export class TodoRepository {
   createItem(input: CreateItemInput): TodoItem {
     const now = new Date().toISOString();
     const result = this.db.execute(
-      `INSERT INTO todo_items (project_id, column_id, title, description, assignee_id, creator_id, priority, start_date, due_date, completed_at, order_index, milestone_id, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @columnId, @title, @description, @assigneeId, @creatorId, @priority, NULL, @dueDate, NULL, @orderIndex, @milestoneId, @createdAt, @updatedAt, NULL)`,
+      `INSERT INTO todo_items (project_id, column_id, title, description, assignee_id, creator_id, priority, start_date, due_date, completed_at, order_index, milestone_id, tags, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @columnId, @title, @description, @assigneeId, @creatorId, @priority, @startDate, @dueDate, NULL, @orderIndex, @milestoneId, @tags, @createdAt, @updatedAt, NULL)`,
       {
         projectId: input.projectId,
         columnId: input.columnId,
@@ -203,9 +209,11 @@ export class TodoRepository {
         assigneeId: input.assigneeId ?? null,
         creatorId: input.creatorId,
         priority: input.priority ?? 'normal',
+        startDate: input.startDate ?? null,
         dueDate: input.dueDate ?? null,
         orderIndex: input.orderIndex,
         milestoneId: null,
+        tags: input.tags ?? null,
         createdAt: now,
         updatedAt: now,
       }
@@ -237,10 +245,18 @@ export class TodoRepository {
       fields.push('priority = @priority');
       params.priority = input.priority;
     }
+    if (input.startDate !== undefined) {
+      fields.push('start_date = @startDate');
+      params.startDate = input.startDate;
+    }
     if (input.dueDate !== undefined) {
       fields.push('due_date = @dueDate');
       params.dueDate = input.dueDate;
     }
+    if (input.tags !== undefined) {
+      fields.push('tags = @tags');
+      params.tags = input.tags;
+    }
     if (input.completedAt !== undefined) {
       fields.push('completed_at = @completedAt');
       params.completedAt = input.completedAt;

repositories/UserRepository.ts

@@ -1,5 +1,5 @@
 import type { SqliteDatabase } from '@/lib/db/sqlite';
-import type { User, UserRole, UserStatus } from '@/lib/types';
+import type { Locale, Theme, User, UserRole, UserStatus } from '@/lib/types';
 
 interface UserRow {
   id: number;
@@ -9,6 +9,8 @@ interface UserRow {
   avatar_url: string | null;
   role: string;
   status: string;
+  theme: string;
+  locale: string;
   created_at: string;
   updated_at: string;
 }
@@ -22,6 +24,8 @@ function mapUser(row: UserRow): User {
     avatarUrl: row.avatar_url,
     role: row.role as UserRole,
     status: row.status as UserStatus,
+    theme: row.theme as Theme,
+    locale: row.locale as Locale,
     createdAt: row.created_at,
     updatedAt: row.updated_at,
   };
@@ -40,6 +44,8 @@ export interface UpdateUserInput {
   avatarUrl?: string | null;
   role?: UserRole;
   status?: UserStatus;
+  theme?: Theme;
+  locale?: Locale;
 }
 
 /**
@@ -114,6 +120,14 @@ export class UserRepository {
       fields.push('status = @status');
       params.status = input.status;
     }
+    if (input.theme !== undefined) {
+      fields.push('theme = @theme');
+      params.theme = input.theme;
+    }
+    if (input.locale !== undefined) {
+      fields.push('locale = @locale');
+      params.locale = input.locale;
+    }
 
     this.db.execute(
       `UPDATE users SET ${fields.join(', ')} WHERE id = @id`,

scripts/generate-icons.mjs

@@ -0,0 +1,26 @@
+// One-off: rasterize public/icon.svg into 512 and 192 PNGs (any/maskable).
+// Uses sharp (already a transitive dependency in this project). Run: node scripts/generate-icons.mjs
+import sharp from 'sharp';
+import fs from 'node:fs';
+import path from 'node:path';
+
+const ROOT = process.cwd();
+const SVG = path.join(ROOT, 'public/icon.svg');
+
+async function main() {
+  const svgBuf = fs.readFileSync(SVG);
+  const sizes = [512, 192];
+  for (const size of sizes) {
+    const out = path.join(ROOT, `public/icon-${size}.png`);
+    await sharp(svgBuf, { density: 384 })
+      .resize(size, size, { fit: 'contain' })
+      .png()
+      .toFile(out);
+    console.log(`wrote ${out} (${size}x${size})`);
+  }
+}
+
+main().catch((err) => {
+  console.error(err);
+  process.exit(1);
+});

scripts/seed-demo.ts

@@ -8,91 +8,15 @@
  * 注意: 既存のDBファイルとuploadsディレクトリを削除してから再作成します
  *       (デモ用途のため、冪等に再実行できるようにリセット方式を採用)。
  *
- * 投入内容: 管理者1名 + 一般ユーザー5名、プロジェクト3件、各プロジェクトに
+ * 投入内容: 管理者1名 + 一般ユーザー約29名、プロジェクト約15件、各プロジェクトに
  * 掲示板/チャット/ToDo/メモ/ファイル/カレンダー/マイルストーン/ミーティング/
- * 通知/アクティビティログを網羅。
+ * 通知/アクティビティログを網羅(従来比 約5倍)。生成内容は固定シードで決定論的。
  */
 import fs from 'node:fs';
 import path from 'node:path';
-import bcrypt from 'bcrypt';
 import { SqliteDatabase } from '../lib/db/sqlite';
 import { Migrator } from '../lib/db/migrator';
-
-const BCRYPT_ROUNDS = 10;
-const now = () => new Date().toISOString();
-const daysFromNow = (d: number) => {
-  const dt = new Date();
-  dt.setDate(dt.getDate() + d);
-  return dt.toISOString();
-};
-const dayStr = (d: number) => daysFromNow(d).slice(0, 10);
-
-interface UserSeed {
-  name: string;
-  email: string;
-  password: string;
-  role: 'system_admin' | 'member';
-  status: 'active' | 'inactive';
-}
-
-const USERS: UserSeed[] = [
-  {
-    name: 'Admin User',
-    email: 'admin@example.com',
-    password: 'admin123',
-    role: 'system_admin',
-    status: 'active',
-  },
-  {
-    name: 'Alice Tanaka',
-    email: 'alice@example.com',
-    password: 'password',
-    role: 'member',
-    status: 'active',
-  },
-  {
-    name: 'Bob Sato',
-    email: 'bob@example.com',
-    password: 'password',
-    role: 'member',
-    status: 'active',
-  },
-  {
-    name: 'Carol Yamada',
-    email: 'carol@example.com',
-    password: 'password',
-    role: 'member',
-    status: 'active',
-  },
-  {
-    name: 'Dave Suzuki',
-    email: 'dave@example.com',
-    password: 'password',
-    role: 'member',
-    status: 'active',
-  },
-  {
-    name: 'Eve Mori (inactive)',
-    email: 'eve@example.com',
-    password: 'password',
-    role: 'member',
-    status: 'inactive',
-  },
-];
-
-// 1x1 透明PNG(ファイル共有デモ用)
-const PNG_BYTES = Buffer.from(
-  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=',
-  'base64'
-);
-
-function insert(
-  db: SqliteDatabase,
-  sql: string,
-  params: Record<string, unknown> = {}
-): number {
-  return Number(db.execute(sql, params).lastInsertRowid);
-}
+import { seedAll } from './seed/generators';
 
 function resetStorage(dbPath: string, uploadsDir: string): void {
   for (const p of [dbPath, `${dbPath}-wal`, `${dbPath}-shm`]) {
@@ -103,565 +27,6 @@ function resetStorage(dbPath: string, uploadsDir: string): void {
   fs.mkdirSync(uploadsDir, { recursive: true });
 }
 
-function seedUsers(db: SqliteDatabase): Map<string, number> {
-  const ids = new Map<string, number>();
-  for (const u of USERS) {
-    const id = insert(
-      db,
-      `INSERT INTO users (name, email, password_hash, avatar_url, role, status, created_at, updated_at)
-       VALUES (@name, @email, @passwordHash, NULL, @role, @status, @createdAt, @updatedAt)`,
-      {
-        name: u.name,
-        email: u.email,
-        passwordHash: bcrypt.hashSync(u.password, BCRYPT_ROUNDS),
-        role: u.role,
-        status: u.status,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-    ids.set(u.email, id);
-  }
-  return ids;
-}
-
-interface ProjectSeed {
-  name: string;
-  description: string;
-  status: 'active' | 'on_hold' | 'completed' | 'archived';
-  owner: string; // email
-  members: { email: string; role: 'admin' | 'member' | 'guest' }[];
-}
-
-const PROJECTS: ProjectSeed[] = [
-  {
-    name: 'Website Redesign',
-    description: 'コーポレートサイトの全面リニューアルプロジェクト',
-    status: 'active',
-    owner: 'alice@example.com',
-    members: [
-      { email: 'bob@example.com', role: 'member' },
-      { email: 'carol@example.com', role: 'member' },
-    ],
-  },
-  {
-    name: 'Mobile App v2',
-    description: 'iOS/Androidアプリの次期メジャーバージョン開発',
-    status: 'active',
-    owner: 'bob@example.com',
-    members: [
-      { email: 'alice@example.com', role: 'member' },
-      { email: 'dave@example.com', role: 'member' },
-    ],
-  },
-  {
-    name: 'Marketing Campaign Q4',
-    description: '第4四半期マーケティングキャンペーンの企画・実行',
-    status: 'on_hold',
-    owner: 'carol@example.com',
-    members: [
-      { email: 'alice@example.com', role: 'member' },
-      { email: 'bob@example.com', role: 'member' },
-      { email: 'dave@example.com', role: 'guest' },
-    ],
-  },
-];
-
-function addMember(
-  db: SqliteDatabase,
-  projectId: number,
-  userId: number,
-  role: string
-): void {
-  insert(
-    db,
-    `INSERT INTO project_members (project_id, user_id, role, joined_at)
-     VALUES (@projectId, @userId, @role, @joinedAt)`,
-    { projectId, userId, role, joinedAt: now() }
-  );
-}
-
-function seedBoard(
-  db: SqliteDatabase,
-  projectId: number,
-  authorIds: number[]
-): void {
-  const threads = [
-    {
-      title: 'デザイン方針について',
-      body: '# デザイン方針\n\n- シンプルさを重視\n- モバイルファースト\n\nご意見ください。',
-      category: 'decision',
-      pinned: 1,
-      important: 1,
-    },
-    {
-      title: '週次進捗報告',
-      body: '今週の進捗を共有します。\n\n| タスク | 状態 |\n|---|---|\n| トップ画面 | 完了 |\n| About画面 | 進行中 |',
-      category: 'minutes',
-      pinned: 0,
-      important: 0,
-    },
-    {
-      title: 'FAQ: ログインできない',
-      body: 'ログインできない場合のトラブルシューティングです。',
-      category: 'trouble',
-      pinned: 0,
-      important: 0,
-    },
-  ];
-  for (const t of threads) {
-    const author = authorIds[0];
-    const threadId = insert(
-      db,
-      `INSERT INTO board_threads (project_id, title, body_md, author_id, category, is_pinned, is_important, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @title, @bodyMd, @authorId, @category, @isPinned, @isImportant, @createdAt, @updatedAt, NULL)`,
-      {
-        projectId,
-        title: t.title,
-        bodyMd: t.body,
-        authorId: author,
-        category: t.category,
-        isPinned: t.pinned,
-        isImportant: t.important,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-    // コメント
-    const commenter = authorIds[1] ?? author;
-    insert(
-      db,
-      `INSERT INTO board_comments (thread_id, author_id, body_md, created_at, updated_at, deleted_at)
-       VALUES (@threadId, @authorId, @bodyMd, @createdAt, @updatedAt, NULL)`,
-      {
-        threadId,
-        authorId: commenter,
-        bodyMd: '確認しました。ありがとうございます！',
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-  }
-}
-
-function seedChat(
-  db: SqliteDatabase,
-  projectId: number,
-  authorIds: number[]
-): void {
-  const messages = [
-    { author: 0, body: 'おはようございます！今日もよろしくお願いします。' },
-    {
-      author: 1,
-      body: 'おつですー。 @alice@example.com ちょっと確認したいことあります',
-    },
-    { author: 0, body: '何でしょう？' },
-    { author: 1, body: 'デザインのカラーパレット、これで確定で大丈夫ですか？' },
-    { author: 0, body: '問題ないです！進めましょう :)' },
-  ];
-  for (const m of messages) {
-    insert(
-      db,
-      `INSERT INTO chat_messages (project_id, author_id, body, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @authorId, @body, @createdAt, @updatedAt, NULL)`,
-      {
-        projectId,
-        authorId: authorIds[m.author],
-        body: m.body,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-  }
-}
-
-function seedTodos(
-  db: SqliteDatabase,
-  projectId: number,
-  memberIds: number[],
-  milestoneIds: number[]
-): void {
-  const columns = ['Backlog', 'To Do', 'In Progress', 'Review', 'Done'];
-  const colIds: number[] = [];
-  columns.forEach((name, idx) => {
-    colIds.push(
-      insert(
-        db,
-        `INSERT INTO todo_columns (project_id, name, order_index, created_at, updated_at)
-         VALUES (@projectId, @name, @orderIndex, @createdAt, @updatedAt)`,
-        { projectId, name, orderIndex: idx, createdAt: now(), updatedAt: now() }
-      )
-    );
-  });
-
-  const items = [
-    {
-      col: 0,
-      title: 'アイデア募集: ヘッダー案',
-      priority: 'low',
-      assignee: null,
-      due: null,
-      milestone: null,
-      completed: false,
-    },
-    {
-      col: 1,
-      title: 'トップ画面の実装',
-      priority: 'high',
-      assignee: 0,
-      due: dayStr(2),
-      milestone: 0,
-      completed: false,
-    },
-    {
-      col: 1,
-      title: 'About画面の実装',
-      priority: 'normal',
-      assignee: 1,
-      due: dayStr(5),
-      milestone: 0,
-      completed: false,
-    },
-    {
-      col: 2,
-      title: '問い合わせフォーム',
-      priority: 'normal',
-      assignee: 0,
-      due: dayStr(7),
-      milestone: 1,
-      completed: false,
-    },
-    {
-      col: 3,
-      title: 'デザインレビュー',
-      priority: 'high',
-      assignee: 1,
-      due: dayStr(1),
-      milestone: 1,
-      completed: false,
-    },
-    {
-      col: 4,
-      title: '要件定義',
-      priority: 'normal',
-      assignee: 0,
-      due: dayStr(-3),
-      milestone: 0,
-      completed: true,
-    },
-    {
-      col: 4,
-      title: 'ワイヤフレーム',
-      priority: 'normal',
-      assignee: 1,
-      due: dayStr(-1),
-      milestone: 0,
-      completed: true,
-    },
-  ];
-  items.forEach((it, idx) => {
-    const assigneeId = it.assignee === null ? null : memberIds[it.assignee];
-    const milestoneId =
-      it.milestone === null ? null : milestoneIds[it.milestone];
-    insert(
-      db,
-      `INSERT INTO todo_items (project_id, column_id, title, description, assignee_id, creator_id, priority, start_date, due_date, completed_at, order_index, milestone_id, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @columnId, @title, @description, @assigneeId, @creatorId, @priority, NULL, @dueDate, @completedAt, @orderIndex, @milestoneId, @createdAt, @updatedAt, NULL)`,
-      {
-        projectId,
-        columnId: colIds[it.col],
-        title: it.title,
-        description: 'デモ用タスクです。',
-        assigneeId,
-        creatorId: memberIds[0],
-        priority: it.priority,
-        dueDate: it.due,
-        completedAt: it.completed ? now() : null,
-        orderIndex: idx,
-        milestoneId,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-  });
-}
-
-function seedNotes(
-  db: SqliteDatabase,
-  projectId: number,
-  authorIds: number[]
-): void {
-  const notes = [
-    {
-      title: 'ミーティングメモ',
-      body: '# ミーティングメモ\n\n## 決定事項\n- カラーテーマ: 青\n- リリース: 来月\n\n## 宿題\n- [ ] デザイン作成\n- [ ] レビュー',
-      tags: 'meeting,notes',
-      pinned: 1,
-    },
-    {
-      title: '技術メモ',
-      body: '## 技術スタック\n\n- Next.js 15\n- SQLite\n- Tailwind CSS\n\n```ts\nconst x = 1;\n```',
-      tags: 'tech',
-      pinned: 0,
-    },
-    {
-      title: 'アイデア',
-      body: '面白い機能のアイデアをメモしておく場所。',
-      tags: null,
-      pinned: 0,
-    },
-  ];
-  for (const n of notes) {
-    insert(
-      db,
-      `INSERT INTO project_notes (project_id, title, body_md, tags, is_pinned, created_by_id, updated_by_id, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @title, @bodyMd, @tags, @isPinned, @createdById, @updatedById, @createdAt, @updatedAt, NULL)`,
-      {
-        projectId,
-        title: n.title,
-        bodyMd: n.body,
-        tags: n.tags,
-        isPinned: n.pinned,
-        createdById: authorIds[0],
-        updatedById: authorIds[0],
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-  }
-}
-
-function seedFiles(
-  db: SqliteDatabase,
-  projectId: number,
-  uploaderId: number,
-  uploadsDir: string
-): void {
-  const dir = path.join(uploadsDir, String(projectId));
-  fs.mkdirSync(dir, { recursive: true });
-
-  // 画像ファイル
-  const imgName = `${crypto.randomUUID()}.png`;
-  const imgPath = path.join(dir, imgName);
-  fs.writeFileSync(imgPath, PNG_BYTES);
-  insert(
-    db,
-    `INSERT INTO file_assets (project_id, uploader_id, filename, original_name, mime_type, size, path, created_at, deleted_at)
-     VALUES (@projectId, @uploaderId, @filename, @originalName, @mimeType, @size, @path, @createdAt, NULL)`,
-    {
-      projectId,
-      uploaderId,
-      filename: imgName,
-      originalName: 'sample-diagram.png',
-      mimeType: 'image/png',
-      size: PNG_BYTES.length,
-      path: imgPath,
-      createdAt: now(),
-    }
-  );
-
-  // テキストファイル
-  const txtName = `${crypto.randomUUID()}.txt`;
-  const txtPath = path.join(dir, txtName);
-  const txtContent =
-    'これはデモ用テキストファイルです。\nシードスクリプトによって生成されました。';
-  fs.writeFileSync(txtPath, txtContent, 'utf-8');
-  insert(
-    db,
-    `INSERT INTO file_assets (project_id, uploader_id, filename, original_name, mime_type, size, path, created_at, deleted_at)
-     VALUES (@projectId, @uploaderId, @filename, @originalName, @mimeType, @size, @path, @createdAt, NULL)`,
-    {
-      projectId,
-      uploaderId,
-      filename: txtName,
-      originalName: 'spec-notes.txt',
-      mimeType: 'text/plain',
-      size: Buffer.byteLength(txtContent),
-      path: txtPath,
-      createdAt: now(),
-    }
-  );
-}
-
-function seedMilestones(db: SqliteDatabase, projectId: number): number[] {
-  const ms = [
-    { title: 'M1: デザイン完了', due: dayStr(7) },
-    { title: 'M2: 実装完了', due: dayStr(21) },
-  ];
-  const ids: number[] = [];
-  for (const m of ms) {
-    ids.push(
-      insert(
-        db,
-        `INSERT INTO milestones (project_id, title, description, due_date, status, created_at, updated_at, deleted_at)
-         VALUES (@projectId, @title, @description, @dueDate, 'open', @createdAt, @updatedAt, NULL)`,
-        {
-          projectId,
-          title: m.title,
-          description: 'マイルストーンです。',
-          dueDate: m.due,
-          createdAt: now(),
-          updatedAt: now(),
-        }
-      )
-    );
-  }
-  return ids;
-}
-
-function seedCalendar(
-  db: SqliteDatabase,
-  projectId: number,
-  creatorId: number
-): void {
-  const events = [
-    {
-      title: '定例ミーティング',
-      type: 'meeting',
-      start: daysFromNow(1),
-      end: daysFromNow(1),
-    },
-    {
-      title: 'デザインレビュー',
-      type: 'reminder',
-      start: daysFromNow(3),
-      end: null,
-    },
-    { title: 'リリース締切', type: 'deadline', start: dayStr(14), end: null },
-  ];
-  for (const e of events) {
-    insert(
-      db,
-      `INSERT INTO calendar_events (project_id, title, description, type, start_at, end_at, created_by_id, related_todo_id, related_milestone_id, related_meeting_id, created_at, updated_at, deleted_at)
-       VALUES (@projectId, @title, @description, @type, @startAt, @endAt, @createdById, NULL, NULL, NULL, @createdAt, @updatedAt, NULL)`,
-      {
-        projectId,
-        title: e.title,
-        description: 'カレンダーイベントです。',
-        type: e.type,
-        startAt: e.start,
-        endAt: e.end,
-        createdById: creatorId,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-  }
-}
-
-function seedMeetings(
-  db: SqliteDatabase,
-  projectId: number,
-  creatorId: number,
-  memberIds: number[]
-): void {
-  const meetingId = insert(
-    db,
-    `INSERT INTO meetings (project_id, title, description, location, meeting_url, start_at, end_at, agenda_md, minutes_md, created_by_id, created_at, updated_at, deleted_at)
-     VALUES (@projectId, @title, @description, @location, @meetingUrl, @startAt, @endAt, @agendaMd, @minutesMd, @createdById, @createdAt, @updatedAt, NULL)`,
-    {
-      projectId,
-      title: '週次定例ミーティング',
-      description: '進捗確認と課題共有',
-      location: '会議室A / オンライン',
-      meetingUrl: 'https://meet.example.com/abc-defg-hij',
-      startAt: daysFromNow(2),
-      endAt: daysFromNow(2),
-      agendaMd: '# アジェンダ\n\n1. 進捗共有\n2. ブロッカー確認\n3. 次週の計画',
-      minutesMd: '# 議事録\n\n- トップ画面は完了\n- About画面は来週完了予定',
-      createdById: creatorId,
-      createdAt: now(),
-      updatedAt: now(),
-    }
-  );
-  for (const uid of memberIds) {
-    insert(
-      db,
-      `INSERT INTO meeting_members (meeting_id, user_id, status) VALUES (@meetingId, @userId, 'invited')`,
-      { meetingId, userId: uid }
-    );
-  }
-}
-
-function seedNotifications(
-  db: SqliteDatabase,
-  projectId: number,
-  memberIds: number[]
-): void {
-  const notifs = [
-    {
-      user: 0,
-      type: 'mention',
-      title: 'メンションされました',
-      body: 'チャットでメンションされました',
-    },
-    {
-      user: 1,
-      type: 'todo_assigned',
-      title: 'ToDoが割り当てられました',
-      body: 'トップ画面の実装',
-    },
-    {
-      user: 0,
-      type: 'meeting_invited',
-      title: 'ミーティングに招待されました',
-      body: '週次定例ミーティング',
-    },
-  ];
-  for (const n of notifs) {
-    insert(
-      db,
-      `INSERT INTO notifications (user_id, project_id, type, title, body, read_at, created_at)
-       VALUES (@userId, @projectId, @type, @title, @body, NULL, @createdAt)`,
-      {
-        userId: memberIds[n.user],
-        projectId,
-        type: n.type,
-        title: n.title,
-        body: n.body,
-        createdAt: now(),
-      }
-    );
-  }
-}
-
-function seedActivityLogs(
-  db: SqliteDatabase,
-  projectId: number,
-  actorIds: number[]
-): void {
-  const logs = [
-    { actor: 0, action: 'board_posted', targetType: 'thread', targetId: 1 },
-    { actor: 1, action: 'comment_added', targetType: 'comment', targetId: 1 },
-    { actor: 0, action: 'todo_created', targetType: 'todo', targetId: 1 },
-    { actor: 1, action: 'todo_completed', targetType: 'todo', targetId: 6 },
-    { actor: 0, action: 'file_uploaded', targetType: 'file', targetId: 1 },
-    { actor: 0, action: 'meeting_created', targetType: 'meeting', targetId: 1 },
-    { actor: 1, action: 'note_updated', targetType: 'note', targetId: 1 },
-    {
-      actor: 0,
-      action: 'milestone_updated',
-      targetType: 'milestone',
-      targetId: 1,
-    },
-  ];
-  for (const l of logs) {
-    insert(
-      db,
-      `INSERT INTO activity_logs (project_id, actor_id, action, target_type, target_id, metadata_json, created_at)
-       VALUES (@projectId, @actorId, @action, @targetType, @targetId, NULL, @createdAt)`,
-      {
-        projectId,
-        actorId: actorIds[l.actor],
-        action: l.action,
-        targetType: l.targetType,
-        targetId: l.targetId,
-        createdAt: now(),
-      }
-    );
-  }
-}
-
 function main(): void {
   const dbPath = process.env.SQLITE_PATH ?? './data/app.db';
   const uploadsDir = process.env.UPLOADS_PATH ?? './data/uploads';
@@ -675,54 +40,18 @@ function main(): void {
     path.join(process.cwd(), 'lib', 'db', 'migrations')
   ).migrate();
 
-  console.log('Seeding users...');
-  const userIds = seedUsers(db);
-
-  let projectCount = 0;
-  for (const p of PROJECTS) {
-    const ownerId = userIds.get(p.owner)!;
-    const projectId = insert(
-      db,
-      `INSERT INTO projects (name, description, status, owner_id, created_at, updated_at)
-       VALUES (@name, @description, @status, @ownerId, @createdAt, @updatedAt)`,
-      {
-        name: p.name,
-        description: p.description,
-        status: p.status,
-        ownerId,
-        createdAt: now(),
-        updatedAt: now(),
-      }
-    );
-    addMember(db, projectId, ownerId, 'admin');
-    const memberIds = [ownerId];
-    for (const m of p.members) {
-      const uid = userIds.get(m.email)!;
-      addMember(db, projectId, uid, m.role);
-      if (!memberIds.includes(uid)) memberIds.push(uid);
-    }
-
-    const milestoneIds = seedMilestones(db, projectId);
-    seedBoard(db, projectId, memberIds);
-    seedChat(db, projectId, memberIds);
-    seedTodos(db, projectId, memberIds, milestoneIds);
-    seedNotes(db, projectId, memberIds);
-    seedFiles(db, projectId, ownerId, uploadsDir);
-    seedCalendar(db, projectId, ownerId);
-    seedMeetings(db, projectId, ownerId, memberIds);
-    seedNotifications(db, projectId, memberIds);
-    seedActivityLogs(db, projectId, memberIds);
-    projectCount++;
-  }
+  console.log('Seeding demo data (~5x volume)...');
+  const { userCount, projectCount } = seedAll(db, uploadsDir);
 
   db.close();
 
   console.log('\n=== Seed complete ===');
-  console.log(`Users: ${USERS.length} | Projects: ${projectCount}`);
+  console.log(`Users: ${userCount} | Projects: ${projectCount}`);
   console.log('\nLogin credentials:');
   console.log('  Admin:    admin@example.com / admin123   (system_admin)');
   console.log('  Users:    alice / bob / carol / dave @example.com / password');
   console.log('  Inactive: eve@example.com / password     (ログイン不可)');
+  console.log('  Others:   <firstname>.<lastname>@example.com / password');
   console.log('\nStart the app with:  npm run dev   ->  http://localhost:3000');
 }
 

scripts/seed/content.ts

@@ -0,0 +1,233 @@
+/**
+ * プロジェクト単位のコンテンツ生成器(掲示板/チャット/ToDo/メモ/ファイル)。
+ * いずれもFK順を担保し、挿入した実IDを呼び出し側へ返す。
+ */
+import fs from 'node:fs';
+import path from 'node:path';
+import type { SqliteDatabase } from '@/lib/db/sqlite';
+import { chance, pick, randInt, seededUuid, type Rng } from './rng';
+import {
+  BOARD_CATEGORIES,
+  BOARD_TITLES,
+  CHAT_PHRASES,
+  NOTE_TAGS,
+  NOTE_TITLES,
+  TODO_PRIORITIES,
+  TODO_TITLES,
+  markdownBody,
+  sentence,
+} from './pools';
+import { PNG_BYTES, dayStr, insert, now } from './helpers';
+
+export function seedBoard(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[]
+): { threadIds: number[]; commentIds: number[] } {
+  const threadIds: number[] = [];
+  const commentIds: number[] = [];
+  const count = randInt(rng, 3, 5);
+  for (let i = 0; i < count; i++) {
+    const title = pick(rng, BOARD_TITLES);
+    const threadId = insert(
+      db,
+      `INSERT INTO board_threads (project_id, title, body_md, author_id, category, is_pinned, is_important, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @title, @bodyMd, @authorId, @category, @isPinned, @isImportant, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        title,
+        bodyMd: markdownBody(rng, title),
+        authorId: pick(rng, memberIds),
+        category: pick(rng, BOARD_CATEGORIES),
+        isPinned: chance(rng, 0.15) ? 1 : 0,
+        isImportant: chance(rng, 0.2) ? 1 : 0,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    threadIds.push(threadId);
+    const commentCount = randInt(rng, 0, 2);
+    for (let c = 0; c < commentCount; c++) {
+      const cid = insert(
+        db,
+        `INSERT INTO board_comments (thread_id, author_id, body_md, created_at, updated_at, deleted_at)
+         VALUES (@threadId, @authorId, @bodyMd, @createdAt, @updatedAt, NULL)`,
+        {
+          threadId,
+          authorId: pick(rng, memberIds),
+          bodyMd: pick(rng, CHAT_PHRASES),
+          createdAt: now(),
+          updatedAt: now(),
+        }
+      );
+      commentIds.push(cid);
+    }
+  }
+  return { threadIds, commentIds };
+}
+
+export function seedChat(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[]
+): number[] {
+  const ids: number[] = [];
+  const count = randInt(rng, 5, 8);
+  for (let i = 0; i < count; i++) {
+    const id = insert(
+      db,
+      `INSERT INTO chat_messages (project_id, author_id, body, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @authorId, @body, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        authorId: pick(rng, memberIds),
+        body: pick(rng, CHAT_PHRASES),
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    ids.push(id);
+  }
+  return ids;
+}
+
+export function seedTodos(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[],
+  milestoneIds: number[]
+): number[] {
+  const columns = ['Backlog', 'To Do', 'In Progress', 'Review', 'Done'];
+  const colIds = columns.map((name, idx) =>
+    insert(
+      db,
+      `INSERT INTO todo_columns (project_id, name, order_index, created_at, updated_at)
+       VALUES (@projectId, @name, @orderIndex, @createdAt, @updatedAt)`,
+      { projectId, name, orderIndex: idx, createdAt: now(), updatedAt: now() }
+    )
+  );
+  const ids: number[] = [];
+  const count = randInt(rng, 7, 10);
+  for (let i = 0; i < count; i++) {
+    const colIdx = randInt(rng, 0, columns.length - 1);
+    const completed = colIdx === columns.length - 1;
+    const id = insert(
+      db,
+      `INSERT INTO todo_items (project_id, column_id, title, description, assignee_id, creator_id, priority, start_date, due_date, completed_at, order_index, milestone_id, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @columnId, @title, @description, @assigneeId, @creatorId, @priority, NULL, @dueDate, @completedAt, @orderIndex, @milestoneId, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        columnId: colIds[colIdx]!,
+        title: pick(rng, TODO_TITLES),
+        description: 'デモ用タスクです。',
+        assigneeId: chance(rng, 0.8) ? pick(rng, memberIds) : null,
+        creatorId: memberIds[0]!,
+        priority: pick(rng, TODO_PRIORITIES),
+        dueDate: chance(rng, 0.7) ? dayStr(randInt(rng, -10, 30)) : null,
+        completedAt: completed ? now() : null,
+        orderIndex: i,
+        milestoneId:
+          chance(rng, 0.6) && milestoneIds.length > 0
+            ? pick(rng, milestoneIds)
+            : null,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    ids.push(id);
+  }
+  return ids;
+}
+
+export function seedNotes(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[]
+): number[] {
+  const ids: number[] = [];
+  const count = randInt(rng, 3, 5);
+  for (let i = 0; i < count; i++) {
+    const authorId = pick(rng, memberIds);
+    const title = pick(rng, NOTE_TITLES);
+    const id = insert(
+      db,
+      `INSERT INTO project_notes (project_id, title, body_md, tags, is_pinned, created_by_id, updated_by_id, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @title, @bodyMd, @tags, @isPinned, @createdById, @updatedById, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        title,
+        bodyMd: markdownBody(rng, title),
+        tags: pick(rng, NOTE_TAGS),
+        isPinned: chance(rng, 0.2) ? 1 : 0,
+        createdById: authorId,
+        updatedById: authorId,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    ids.push(id);
+  }
+  return ids;
+}
+
+export function seedFiles(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  uploaderId: number,
+  uploadsDir: string
+): number[] {
+  const dir = path.join(uploadsDir, String(projectId));
+  fs.mkdirSync(dir, { recursive: true });
+  const ids: number[] = [];
+  const count = randInt(rng, 2, 4);
+  for (let i = 0; i < count; i++) {
+    if (chance(rng, 0.5)) {
+      const filename = `${seededUuid(rng)}.png`;
+      const filePath = path.join(dir, filename);
+      fs.writeFileSync(filePath, PNG_BYTES);
+      const id = insert(
+        db,
+        `INSERT INTO file_assets (project_id, uploader_id, filename, original_name, mime_type, size, path, created_at, deleted_at)
+         VALUES (@projectId, @uploaderId, @filename, @originalName, @mimeType, @size, @path, @createdAt, NULL)`,
+        {
+          projectId,
+          uploaderId,
+          filename,
+          originalName: `diagram-${i + 1}.png`,
+          mimeType: 'image/png',
+          size: PNG_BYTES.length,
+          path: filePath,
+          createdAt: now(),
+        }
+      );
+      ids.push(id);
+    } else {
+      const filename = `${seededUuid(rng)}.txt`;
+      const filePath = path.join(dir, filename);
+      const content = `デモ用テキストファイル ${i + 1}。\n${sentence(rng)}`;
+      fs.writeFileSync(filePath, content, 'utf-8');
+      const id = insert(
+        db,
+        `INSERT INTO file_assets (project_id, uploader_id, filename, original_name, mime_type, size, path, created_at, deleted_at)
+         VALUES (@projectId, @uploaderId, @filename, @originalName, @mimeType, @size, @path, @createdAt, NULL)`,
+        {
+          projectId,
+          uploaderId,
+          filename,
+          originalName: `notes-${i + 1}.txt`,
+          mimeType: 'text/plain',
+          size: Buffer.byteLength(content),
+          path: filePath,
+          createdAt: now(),
+        }
+      );
+      ids.push(id);
+    }
+  }
+  return ids;
+}

scripts/seed/generators.ts

@@ -0,0 +1,203 @@
+/**
+ * シードデータ生成のオーケストレータ。
+ * ユーザーとプロジェクトを生成し、各プロジェクト単位の生成器(content.ts)をFK順に呼び出す。
+ * 生成内容は固定シード(mulberry32)で決定論的。
+ */
+import bcrypt from 'bcrypt';
+import type { SqliteDatabase } from '@/lib/db/sqlite';
+import { createRng, pick, pickN, randInt, chance, type Rng } from './rng';
+import {
+  FAMILY_NAMES,
+  GIVEN_NAMES,
+  PROJECT_DESCRIPTIONS,
+  PROJECT_NAMES,
+} from './pools';
+import {
+  CANONICAL_PROJECTS,
+  CANONICAL_USERS,
+  SEED,
+  TARGET_PROJECTS,
+  TARGET_USERS,
+  type UserSeed,
+  addMember,
+  bcryptSalt,
+  insert,
+  now,
+  type ProjectSpec,
+} from './helpers';
+import {
+  seedBoard,
+  seedChat,
+  seedFiles,
+  seedNotes,
+  seedTodos,
+} from './content';
+import { seedCalendar, seedMeetings, seedMilestones } from './schedule';
+import { seedActivityLogs, seedNotifications } from './logs';
+
+function buildUserSeeds(rng: Rng): UserSeed[] {
+  const seeds = [...CANONICAL_USERS];
+  const usedEmails = new Set(seeds.map((u) => u.email));
+  const usedNames = new Set(seeds.map((u) => u.name));
+  while (seeds.length < TARGET_USERS) {
+    const given = pick(rng, GIVEN_NAMES);
+    const family = pick(rng, FAMILY_NAMES);
+    const name = `${given} ${family}`;
+    if (usedNames.has(name)) continue;
+    let email = `${given.toLowerCase()}.${family.toLowerCase()}@example.com`;
+    let suffix = 1;
+    while (usedEmails.has(email)) {
+      email = `${given.toLowerCase()}.${family.toLowerCase()}${suffix}@example.com`;
+      suffix++;
+    }
+    usedEmails.add(email);
+    usedNames.add(name);
+    const status = chance(rng, 0.1) ? 'inactive' : 'active';
+    seeds.push({ name, email, password: 'password', role: 'member', status });
+  }
+  return seeds;
+}
+
+function seedUsers(
+  db: SqliteDatabase,
+  rng: Rng
+): { emailToId: Map<string, number>; activeMemberIds: number[] } {
+  const seeds = buildUserSeeds(rng);
+  const emailToId = new Map<string, number>();
+  const activeMemberIds: number[] = [];
+  for (const u of seeds) {
+    const id = insert(
+      db,
+      `INSERT INTO users (name, email, password_hash, avatar_url, role, status, created_at, updated_at)
+       VALUES (@name, @email, @passwordHash, NULL, @role, @status, @createdAt, @updatedAt)`,
+      {
+        name: u.name,
+        email: u.email,
+        passwordHash: bcrypt.hashSync(u.password, bcryptSalt(rng)),
+        role: u.role,
+        status: u.status,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    emailToId.set(u.email, id);
+    if (u.role === 'member' && u.status === 'active') activeMemberIds.push(id);
+  }
+  return { emailToId, activeMemberIds };
+}
+
+function buildProjectSpecs(rng: Rng): ProjectSpec[] {
+  const specs: ProjectSpec[] = CANONICAL_PROJECTS.map((p) => ({
+    name: p.name,
+    description: p.description,
+    status: p.status,
+    ownerEmail: p.ownerEmail,
+    memberEmails: p.memberEmails,
+  }));
+  const usedNames = new Set(specs.map((s) => s.name));
+  const names = pickN(rng, PROJECT_NAMES, PROJECT_NAMES.length).filter(
+    (n) => !usedNames.has(n)
+  );
+  const descs = pickN(rng, PROJECT_DESCRIPTIONS, PROJECT_DESCRIPTIONS.length);
+  let ni = 0;
+  let di = 0;
+  while (specs.length < TARGET_PROJECTS) {
+    const name = names[ni] ?? `Internal Project ${specs.length + 1}`;
+    ni++;
+    const description = descs[di % descs.length] ?? 'デモ用プロジェクトです。';
+    di++;
+    const r = rng();
+    const status: ProjectSpec['status'] =
+      r < 0.55
+        ? 'active'
+        : r < 0.75
+          ? 'on_hold'
+          : r < 0.9
+            ? 'completed'
+            : 'archived';
+    specs.push({
+      name,
+      description,
+      status,
+      ownerEmail: null,
+      memberEmails: [],
+    });
+  }
+  return specs;
+}
+
+export function seedAll(
+  db: SqliteDatabase,
+  uploadsDir: string
+): { userCount: number; projectCount: number } {
+  const rng = createRng(SEED);
+  const { emailToId, activeMemberIds } = seedUsers(db, rng);
+
+  const specs = buildProjectSpecs(rng);
+  for (const spec of specs) {
+    const ownerId = spec.ownerEmail
+      ? (emailToId.get(spec.ownerEmail) ?? activeMemberIds[0]!)
+      : pick(rng, activeMemberIds);
+    const projectId = insert(
+      db,
+      `INSERT INTO projects (name, description, status, owner_id, created_at, updated_at)
+       VALUES (@name, @description, @status, @ownerId, @createdAt, @updatedAt)`,
+      {
+        name: spec.name,
+        description: spec.description,
+        status: spec.status,
+        ownerId,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    addMember(db, projectId, ownerId, 'admin');
+    const memberIds = [ownerId];
+    const extras =
+      spec.memberEmails.length > 0
+        ? spec.memberEmails.map((m) => ({
+            id: emailToId.get(m.email)!,
+            role: m.role,
+          }))
+        : pickN(
+            rng,
+            activeMemberIds.filter((id) => id !== ownerId),
+            randInt(rng, 2, 4)
+          ).map((id) => ({ id, role: 'member' as const }));
+    for (const m of extras) {
+      if (!memberIds.includes(m.id)) {
+        addMember(db, projectId, m.id, m.role);
+        memberIds.push(m.id);
+      }
+    }
+
+    const milestoneIds = seedMilestones(db, rng, projectId);
+    const { threadIds, commentIds } = seedBoard(db, rng, projectId, memberIds);
+    seedChat(db, rng, projectId, memberIds);
+    const todoIds = seedTodos(db, rng, projectId, memberIds, milestoneIds);
+    const noteIds = seedNotes(db, rng, projectId, memberIds);
+    const fileIds = seedFiles(db, rng, projectId, ownerId, uploadsDir);
+    const meetingIds = seedMeetings(db, rng, projectId, ownerId, memberIds);
+    seedCalendar(
+      db,
+      rng,
+      projectId,
+      ownerId,
+      todoIds,
+      milestoneIds,
+      meetingIds
+    );
+    seedNotifications(db, rng, projectId, memberIds);
+    seedActivityLogs(db, rng, projectId, memberIds, {
+      threadIds,
+      commentIds,
+      todoIds,
+      fileIds,
+      meetingIds,
+      noteIds,
+      milestoneIds,
+    });
+  }
+
+  return { userCount: emailToId.size, projectCount: specs.length };
+}

scripts/seed/helpers.ts

@@ -0,0 +1,170 @@
+/**
+ * シード生成器間で共有する定数・時刻ヘルパ・挿入ヘルパ・カノニカルデータ。
+ */
+import type { SqliteDatabase } from '@/lib/db/sqlite';
+import type { ProjectMemberRole } from '@/lib/types';
+import { type Rng } from './rng';
+
+export const BCRYPT_ROUNDS = 10;
+export const SEED = 0xc0ffee;
+export const TARGET_USERS = 30;
+export const TARGET_PROJECTS = 15;
+
+// 実行日(UTC 0時)を基準にすることで、同日内の再実行で同一データになる。
+const BASE_DATE = (() => {
+  const d = new Date();
+  d.setUTCHours(0, 0, 0, 0);
+  return d;
+})();
+const BASE_TIME = BASE_DATE.toISOString();
+export const now = (): string => BASE_TIME;
+export const daysFromNow = (d: number): string => {
+  const dt = new Date(BASE_DATE);
+  dt.setUTCDate(dt.getUTCDate() + d);
+  return dt.toISOString();
+};
+export const dayStr = (d: number): string => daysFromNow(d).slice(0, 10);
+
+export const PNG_BYTES = Buffer.from(
+  'iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAQAAAC1HAwCAAAAC0lEQVR42mNkYAAAAAYAAjCB0C8AAAAASUVORK5CYII=',
+  'base64'
+);
+
+const BCRYPT_SALT_ALPHABET =
+  './ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789';
+
+export function bcryptSalt(rng: Rng): string {
+  let salt = '';
+  for (let i = 0; i < 22; i++) {
+    salt +=
+      BCRYPT_SALT_ALPHABET[Math.floor(rng() * BCRYPT_SALT_ALPHABET.length)];
+  }
+  return `$2b$${BCRYPT_ROUNDS}$${salt}`;
+}
+
+export interface UserSeed {
+  name: string;
+  email: string;
+  password: string;
+  role: 'system_admin' | 'member';
+  status: 'active' | 'inactive';
+}
+
+export interface ProjectSpec {
+  name: string;
+  description: string;
+  status: 'active' | 'on_hold' | 'completed' | 'archived';
+  ownerEmail: string | null;
+  memberEmails: { email: string; role: 'admin' | 'member' | 'guest' }[];
+}
+
+export interface ActivityContext {
+  threadIds: number[];
+  commentIds: number[];
+  todoIds: number[];
+  fileIds: number[];
+  meetingIds: number[];
+  noteIds: number[];
+  milestoneIds: number[];
+}
+
+export const CANONICAL_USERS: UserSeed[] = [
+  {
+    name: 'Admin User',
+    email: 'admin@example.com',
+    password: 'admin123',
+    role: 'system_admin',
+    status: 'active',
+  },
+  {
+    name: 'Alice Tanaka',
+    email: 'alice@example.com',
+    password: 'password',
+    role: 'member',
+    status: 'active',
+  },
+  {
+    name: 'Bob Sato',
+    email: 'bob@example.com',
+    password: 'password',
+    role: 'member',
+    status: 'active',
+  },
+  {
+    name: 'Carol Yamada',
+    email: 'carol@example.com',
+    password: 'password',
+    role: 'member',
+    status: 'active',
+  },
+  {
+    name: 'Dave Suzuki',
+    email: 'dave@example.com',
+    password: 'password',
+    role: 'member',
+    status: 'active',
+  },
+  {
+    name: 'Eve Mori (inactive)',
+    email: 'eve@example.com',
+    password: 'password',
+    role: 'member',
+    status: 'inactive',
+  },
+];
+
+export const CANONICAL_PROJECTS: ProjectSpec[] = [
+  {
+    name: 'Website Redesign',
+    description: 'コーポレートサイトの全面リニューアルプロジェクト',
+    status: 'active',
+    ownerEmail: 'alice@example.com',
+    memberEmails: [
+      { email: 'bob@example.com', role: 'member' },
+      { email: 'carol@example.com', role: 'member' },
+    ],
+  },
+  {
+    name: 'Mobile App v2',
+    description: 'iOS/Androidアプリの次期メジャーバージョン開発',
+    status: 'active',
+    ownerEmail: 'bob@example.com',
+    memberEmails: [
+      { email: 'alice@example.com', role: 'member' },
+      { email: 'dave@example.com', role: 'member' },
+    ],
+  },
+  {
+    name: 'Marketing Campaign Q4',
+    description: '第4四半期マーケティングキャンペーンの企画・実行',
+    status: 'on_hold',
+    ownerEmail: 'carol@example.com',
+    memberEmails: [
+      { email: 'alice@example.com', role: 'member' },
+      { email: 'bob@example.com', role: 'member' },
+      { email: 'dave@example.com', role: 'guest' },
+    ],
+  },
+];
+
+export function insert(
+  db: SqliteDatabase,
+  sql: string,
+  params: Record<string, unknown> = {}
+): number {
+  return Number(db.execute(sql, params).lastInsertRowid);
+}
+
+export function addMember(
+  db: SqliteDatabase,
+  projectId: number,
+  userId: number,
+  role: ProjectMemberRole
+): void {
+  insert(
+    db,
+    `INSERT INTO project_members (project_id, user_id, role, joined_at)
+     VALUES (@projectId, @userId, @role, @joinedAt)`,
+    { projectId, userId, role, joinedAt: now() }
+  );
+}

scripts/seed/logs.ts

@@ -0,0 +1,70 @@
+/**
+ * 通知とアクティビティログの生成器。アクティビティログは実IDを参照する。
+ */
+import type { SqliteDatabase } from '@/lib/db/sqlite';
+import { chance, pick, randInt, type Rng } from './rng';
+import { ACTIVITY_ACTIONS, NOTIF_TEMPLATES } from './pools';
+import { type ActivityContext, insert, now } from './helpers';
+
+export function seedNotifications(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[]
+): void {
+  const count = randInt(rng, 3, 5);
+  for (let i = 0; i < count; i++) {
+    const t = pick(rng, NOTIF_TEMPLATES);
+    insert(
+      db,
+      `INSERT INTO notifications (user_id, project_id, type, title, body, read_at, created_at)
+       VALUES (@userId, @projectId, @type, @title, @body, @readAt, @createdAt)`,
+      {
+        userId: pick(rng, memberIds),
+        projectId,
+        type: t.type,
+        title: t.title,
+        body: t.body,
+        readAt: chance(rng, 0.3) ? now() : null,
+        createdAt: now(),
+      }
+    );
+  }
+}
+
+export function seedActivityLogs(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  memberIds: number[],
+  ctx: ActivityContext
+): void {
+  const targetsByType: Record<string, number[]> = {
+    thread: ctx.threadIds,
+    comment: ctx.commentIds,
+    todo: ctx.todoIds,
+    file: ctx.fileIds,
+    meeting: ctx.meetingIds,
+    note: ctx.noteIds,
+    milestone: ctx.milestoneIds,
+  };
+  const count = randInt(rng, 8, 12);
+  for (let i = 0; i < count; i++) {
+    const a = pick(rng, ACTIVITY_ACTIONS);
+    const pool = targetsByType[a.targetType] ?? [];
+    if (pool.length === 0) continue;
+    insert(
+      db,
+      `INSERT INTO activity_logs (project_id, actor_id, action, target_type, target_id, metadata_json, created_at)
+       VALUES (@projectId, @actorId, @action, @targetType, @targetId, NULL, @createdAt)`,
+      {
+        projectId,
+        actorId: pick(rng, memberIds),
+        action: a.action,
+        targetType: a.targetType,
+        targetId: pick(rng, pool),
+        createdAt: now(),
+      }
+    );
+  }
+}

scripts/seed/pools.ts

@@ -0,0 +1,374 @@
+/**
+ * シードデータ用のコンテンツプールとテキスト生成ヘルパ。
+ * lib/types/index.ts の列挙型に合わせた値のみを使用する。
+ */
+import type {
+  BoardCategory,
+  CalendarEventType,
+  NotificationType,
+  TodoPriority,
+} from '@/lib/types';
+import { type Rng, chance, pick, pickN, randInt } from './rng';
+
+export const GIVEN_NAMES = [
+  'Frank',
+  'Grace',
+  'Henry',
+  'Ivy',
+  'Jack',
+  'Karen',
+  'Leo',
+  'Mia',
+  'Noah',
+  'Olivia',
+  'Peter',
+  'Quinn',
+  'Rachel',
+  'Sam',
+  'Tina',
+  'Uma',
+  'Victor',
+  'Wendy',
+  'Xander',
+  'Yuki',
+  'Zoe',
+  'Amber',
+  'Brian',
+  'Chloe',
+  'Diego',
+  'Emma',
+  'Finn',
+  'Gina',
+  'Hiro',
+  'Iris',
+  'Jonas',
+  'Kira',
+];
+
+export const FAMILY_NAMES = [
+  'Yamamoto',
+  'Watanabe',
+  'Ito',
+  'Nakamura',
+  'Kobayashi',
+  'Saito',
+  'Takahashi',
+  'Kato',
+  'Yoshida',
+  'Sasaki',
+  'Matsumoto',
+  'Inoue',
+  'Kimura',
+  'Hayashi',
+  'Shimizu',
+  'Yamazaki',
+  'Mori',
+  'Abe',
+  'Ikeda',
+  'Hashimoto',
+  'Yamaguchi',
+  'Kondo',
+  'Ishikawa',
+  'Ogawa',
+];
+
+export const PROJECT_NAMES = [
+  'Website Redesign',
+  'Mobile App v2',
+  'Marketing Campaign Q4',
+  'Data Warehouse Migration',
+  'Security Audit 2026',
+  'HR Portal Revamp',
+  'Customer Support Bot',
+  'API Gateway Upgrade',
+  'Design System 2.0',
+  'Sales CRM Integration',
+  'Cloud Cost Optimization',
+  'Accessibility Audit',
+  'Onboarding Flow Redesign',
+  'Analytics Dashboard',
+  'DevOps Automation',
+  'Internal Wiki Migration',
+  'Payment Gateway v3',
+  'QA Automation Suite',
+];
+
+export const PROJECT_DESCRIPTIONS = [
+  'コーポレートサイトの全面リニューアルプロジェクト',
+  'iOS/Androidアプリの次期メジャーバージョン開発',
+  '第4四半期マーケティングキャンペーンの企画・実行',
+  'レガシーDWHからモダンデータプラットフォームへの移行',
+  '全社システムのセキュリティ監査と是正',
+  '人事ポータルのUX改善と再構築',
+  'カスタマーサポート向けチャットボットの開発',
+  'APIゲートウェイの刷新とレートリミット強化',
+  '組織横断デザインシステムの次世代化',
+  '営業CRMと社内DBの双方向連携',
+  'クラウド利用コストの可視化と削減',
+  '製品アクセシビリティの監査と改善',
+  '新規ユーザーオンボーディングフローの再設計',
+  '経営ダッシュボードの構築とBI連携',
+  'デプロイパイプラインの自動化とCI/CD強化',
+  '社内Wikiの新プラットフォームへの移行',
+  '決済ゲートウェイの次期バージョン開発',
+  '回帰テストの自動化とカバレッジ向上',
+];
+
+export const TODO_TITLES = [
+  '要件定義',
+  'ワイヤフレーム作成',
+  'デザインモックアップ',
+  'フロントエンド実装',
+  'バックエンドAPI実装',
+  'DBスキーマ設計',
+  'ユニットテスト追加',
+  'E2Eテスト作成',
+  'パフォーマンス計測',
+  'セキュリティレビュー',
+  'アクセシビリティ確認',
+  'ドキュメント整備',
+  'デプロイ手順策定',
+  'ロールバック確認',
+  '負荷テスト',
+  'ログ監視設定',
+  'エラーハンドリング整理',
+  'i18n対応',
+  'ダッシュボード実装',
+  '検索機能実装',
+  '認証フロー見直し',
+  'キャッシュ導入',
+  'マニュアル作成',
+  'レビュー対応',
+  'リファクタリング',
+  '依存ライブラリ更新',
+  '本番環境検証',
+  '顧客デモ準備',
+  'マイルストーン調整',
+  'バグトリアージ',
+  'データ移行スクリプト',
+  'バッチジョブ実装',
+  'Webhook連携',
+  'レポート出力',
+  '権限設定見直し',
+];
+
+export const TODO_PRIORITIES: readonly TodoPriority[] = [
+  'low',
+  'normal',
+  'high',
+];
+
+export const NOTE_TITLES = [
+  'ミーティングメモ',
+  '技術メモ',
+  'アイデア',
+  '議事録',
+  '振り返り',
+  '調査メモ',
+  '設計メモ',
+  'QAメモ',
+  'リリースノート案',
+  'トラブル対応記録',
+  'ブレスト',
+  '意思決定ログ',
+  'タスク洗い出し',
+  'インシデント報告',
+  '週報',
+];
+
+export const NOTE_TAGS = [
+  'meeting',
+  'tech',
+  'design',
+  'qa',
+  'release',
+  'idea',
+  'incident',
+  'weekly',
+  null,
+];
+
+export const CHAT_PHRASES = [
+  'おはようございます！',
+  'お疲れ様です。',
+  '進捗どうですか？',
+  '確認お願いします。',
+  'ちょっと相談があります。',
+  '了解しました。',
+  'ありがとうございます！',
+  '後で見ます。',
+  'LGTMです。',
+  'ブロッカー発生しました。',
+  '修正しました。レビューお願いします。',
+  'ミーティングの時間変更できますか？',
+  '資料を共有します。',
+  'いいですね！進めましょう。',
+  '懸念点をまとめました。',
+  'デプロイ完了しました。',
+  'テスト通りました。',
+  'バグを見つけました。',
+  '仕様を再確認しましょう。',
+  '承知しました。',
+];
+
+export const BOARD_TITLES = [
+  'デザイン方針について',
+  '週次進捗報告',
+  'FAQ: ログインできない',
+  'リリース計画の共有',
+  'アーキテクチャレビュー',
+  'スプリント振り返り',
+  '新メンバーへのお知らせ',
+  'トラブルシューティング',
+  '意思決定記録',
+  'テスト戦略',
+  'パフォーマンス改善案',
+  'セキュリティアップデート',
+  '顧客フィードバックまとめ',
+  'ドキュメント整理',
+  '次フェーズの構想',
+];
+
+export const BOARD_CATEGORIES: readonly BoardCategory[] = [
+  'notice',
+  'spec',
+  'minutes',
+  'question',
+  'decision',
+  'trouble',
+  'memo',
+];
+
+export const CALENDAR_TITLES = [
+  '定例ミーティング',
+  'デザインレビュー',
+  'リリース締切',
+  'スプリント計画',
+  '振り返り',
+  '1on1',
+  '全社朝会',
+  '顧客デモ',
+  '技術共有会',
+  '勉強会',
+  '保守ウィンドウ',
+  'デプロイ',
+  'テスト実施日',
+  'キックオフ',
+  '回顧展示',
+];
+
+export const CALENDAR_TYPES: readonly CalendarEventType[] = [
+  'meeting',
+  'deadline',
+  'milestone',
+  'todo',
+  'reminder',
+  'custom',
+];
+
+export const MEETING_TITLES = [
+  '週次定例ミーティング',
+  '設計レビュー会',
+  'スプリント計画会',
+  'リリース判定会',
+  '障害対応ブリーフィング',
+];
+
+export const NOTIF_TEMPLATES: {
+  type: NotificationType;
+  title: string;
+  body: string;
+}[] = [
+  {
+    type: 'mention',
+    title: 'メンションされました',
+    body: 'チャットでメンションされました',
+  },
+  {
+    type: 'todo_assigned',
+    title: 'ToDoが割り当てられました',
+    body: '新しいタスクが担当になりました',
+  },
+  {
+    type: 'todo_due_soon',
+    title: '期限が近づいています',
+    body: 'ToDoの期限が迫っています',
+  },
+  {
+    type: 'meeting_invited',
+    title: 'ミーティングに招待されました',
+    body: 'カレンダーを確認してください',
+  },
+  {
+    type: 'board_commented',
+    title: '掲示板に返信がありました',
+    body: 'あなたのスレッドにコメントがつきました',
+  },
+  {
+    type: 'project_added',
+    title: 'プロジェクトに追加されました',
+    body: '新しいプロジェクトのメンバーになりました',
+  },
+  {
+    type: 'file_shared',
+    title: 'ファイルが共有されました',
+    body: '新しいファイルがアップロードされました',
+  },
+  {
+    type: 'note_updated',
+    title: 'メモが更新されました',
+    body: '担当メモが更新されました',
+  },
+];
+
+export const ACTIVITY_ACTIONS: { action: string; targetType: string }[] = [
+  { action: 'board_posted', targetType: 'thread' },
+  { action: 'comment_added', targetType: 'comment' },
+  { action: 'todo_created', targetType: 'todo' },
+  { action: 'todo_updated', targetType: 'todo' },
+  { action: 'todo_completed', targetType: 'todo' },
+  { action: 'file_uploaded', targetType: 'file' },
+  { action: 'note_created', targetType: 'note' },
+  { action: 'note_updated', targetType: 'note' },
+  { action: 'meeting_created', targetType: 'meeting' },
+  { action: 'milestone_updated', targetType: 'milestone' },
+];
+
+const SENTENCES = [
+  '今週は計画通りに進捗した。',
+  'いくつかのブロッカーを解消した。',
+  '次フェーズのスコープを確定した。',
+  'レビューで指摘事項を整理した。',
+  'パフォーマンス測定を実施した。',
+  'ドキュメントを最新化した。',
+  'テストカバレッジを改善した。',
+  '依存ライブラリを更新した。',
+  '顧客からのフィードバックを反映した。',
+  'インフラ構成を見直した。',
+];
+
+const SECTIONS = ['概要', '背景', '決定事項', '宿題', '次のステップ'];
+
+export function sentence(rng: Rng): string {
+  return pick(rng, SENTENCES);
+}
+
+export function paragraph(rng: Rng, n: number): string {
+  return pickN(rng, SENTENCES, n).join(' ');
+}
+
+export function markdownBody(rng: Rng, heading: string): string {
+  const lines: string[] = [`# ${heading}`, ''];
+  const sectionCount = randInt(rng, 2, 4);
+  const sections = pickN(rng, SECTIONS, sectionCount);
+  for (const s of sections) {
+    lines.push(`## ${s}`, '');
+    lines.push(paragraph(rng, randInt(rng, 2, 3)));
+    if (chance(rng, 0.4)) {
+      lines.push('');
+      lines.push('- 項目A', '- 項目B', '- 項目C');
+    }
+    lines.push('');
+  }
+  return lines.join('\n');
+}

scripts/seed/rng.ts

@@ -0,0 +1,50 @@
+/**
+ * シードデータ生成用の決定論的乱数ユーティリティ。
+ * mulberry32 を用い、固定シードで再現可能なデータを生成する。
+ */
+
+export type Rng = () => number;
+
+export function createRng(seed: number): Rng {
+  let a = seed >>> 0;
+  return () => {
+    a |= 0;
+    a = (a + 0x6d2b79f5) | 0;
+    let t = Math.imul(a ^ (a >>> 15), 1 | a);
+    t = (t + Math.imul(t ^ (t >>> 7), 61 | t)) ^ t;
+    return ((t ^ (t >>> 14)) >>> 0) / 4294967296;
+  };
+}
+
+export function pick<T>(rng: Rng, arr: readonly T[]): T {
+  return arr[Math.floor(rng() * arr.length)]!;
+}
+
+export function pickN<T>(rng: Rng, arr: readonly T[], n: number): T[] {
+  return shuffle(rng, arr).slice(0, Math.min(n, arr.length));
+}
+
+export function randInt(rng: Rng, min: number, max: number): number {
+  return Math.floor(rng() * (max - min + 1)) + min;
+}
+
+export function shuffle<T>(rng: Rng, arr: readonly T[]): T[] {
+  const out = [...arr];
+  for (let i = out.length - 1; i > 0; i--) {
+    const j = Math.floor(rng() * (i + 1));
+    [out[i], out[j]] = [out[j]!, out[i]!];
+  }
+  return out;
+}
+
+export function chance(rng: Rng, p: number): boolean {
+  return rng() < p;
+}
+
+export function seededUuid(rng: Rng): string {
+  const hex = () =>
+    Math.floor(rng() * 0x10000)
+      .toString(16)
+      .padStart(4, '0');
+  return `${hex()}${hex()}-${hex()}-${hex()}-${hex()}-${hex()}${hex()}${hex()}`;
+}

scripts/seed/schedule.ts

@@ -0,0 +1,138 @@
+/**
+ * スケジュール系エンティティの生成器(マイルストーン/ミーティング/カレンダー)。
+ */
+import type { SqliteDatabase } from '@/lib/db/sqlite';
+import type { MeetingMemberStatus, MilestoneStatus } from '@/lib/types';
+import { chance, pick, pickN, randInt, seededUuid, type Rng } from './rng';
+import { CALENDAR_TITLES, CALENDAR_TYPES, MEETING_TITLES } from './pools';
+import { dayStr, daysFromNow, insert, now } from './helpers';
+
+const MILESTONE_STATUS_OPEN: MilestoneStatus = 'open';
+const MEETING_MEMBER_INVITED: MeetingMemberStatus = 'invited';
+
+export function seedMilestones(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number
+): number[] {
+  const ids: number[] = [];
+  const phases = ['計画', '設計', '実装', 'テスト', 'リリース', '振り返り'];
+  const count = randInt(rng, 2, 4);
+  for (let i = 0; i < count; i++) {
+    const id = insert(
+      db,
+      `INSERT INTO milestones (project_id, title, description, due_date, status, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @title, @description, @dueDate, @status, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        title: `M${i + 1}: ${phases[i % phases.length]}完了`,
+        description: 'マイルストーンです。',
+        dueDate: dayStr(randInt(rng, 3, 60)),
+        status: MILESTONE_STATUS_OPEN,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    ids.push(id);
+  }
+  return ids;
+}
+
+export function seedMeetings(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  creatorId: number,
+  memberIds: number[]
+): number[] {
+  const ids: number[] = [];
+  const count = randInt(rng, 1, 2);
+  for (let i = 0; i < count; i++) {
+    const offset = randInt(rng, -5, 30);
+    const id = insert(
+      db,
+      `INSERT INTO meetings (project_id, title, description, location, meeting_url, start_at, end_at, agenda_md, minutes_md, created_by_id, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @title, @description, @location, @meetingUrl, @startAt, @endAt, @agendaMd, @minutesMd, @createdById, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        title: pick(rng, MEETING_TITLES),
+        description: '進捗確認と課題共有',
+        location: pick(rng, [
+          '会議室A',
+          '会議室B',
+          'オンライン',
+          '会議室A / オンライン',
+        ]),
+        meetingUrl: chance(rng, 0.7)
+          ? `https://meet.example.com/${seededUuid(rng).slice(0, 8)}`
+          : null,
+        startAt: daysFromNow(offset),
+        endAt: daysFromNow(offset),
+        agendaMd:
+          '# アジェンダ\n\n1. 進捗共有\n2. ブロッカー確認\n3. 次週の計画',
+        minutesMd: chance(rng, 0.6)
+          ? '# 議事録\n\n- 進捗は順調\n- 課題を共有\n- 次週も継続'
+          : null,
+        createdById: creatorId,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    const attendeeCount = randInt(rng, 2, Math.max(2, memberIds.length));
+    for (const uid of pickN(rng, memberIds, attendeeCount)) {
+      insert(
+        db,
+        `INSERT INTO meeting_members (meeting_id, user_id, status)
+         VALUES (@meetingId, @userId, @status)`,
+        { meetingId: id, userId: uid, status: MEETING_MEMBER_INVITED }
+      );
+    }
+    ids.push(id);
+  }
+  return ids;
+}
+
+export function seedCalendar(
+  db: SqliteDatabase,
+  rng: Rng,
+  projectId: number,
+  creatorId: number,
+  todoIds: number[],
+  milestoneIds: number[],
+  meetingIds: number[]
+): number[] {
+  const ids: number[] = [];
+  const count = randInt(rng, 3, 5);
+  for (let i = 0; i < count; i++) {
+    const type = pick(rng, CALENDAR_TYPES);
+    const offset = randInt(rng, -7, 45);
+    const id = insert(
+      db,
+      `INSERT INTO calendar_events (project_id, title, description, type, start_at, end_at, created_by_id, related_todo_id, related_milestone_id, related_meeting_id, created_at, updated_at, deleted_at)
+       VALUES (@projectId, @title, @description, @type, @startAt, @endAt, @createdById, @relatedTodoId, @relatedMilestoneId, @relatedMeetingId, @createdAt, @updatedAt, NULL)`,
+      {
+        projectId,
+        title: pick(rng, CALENDAR_TITLES),
+        description: 'カレンダーイベントです。',
+        type,
+        startAt: type === 'deadline' ? dayStr(offset) : daysFromNow(offset),
+        endAt: chance(rng, 0.4) ? daysFromNow(offset) : null,
+        createdById: creatorId,
+        relatedTodoId:
+          chance(rng, 0.2) && todoIds.length > 0 ? pick(rng, todoIds) : null,
+        relatedMilestoneId:
+          chance(rng, 0.15) && milestoneIds.length > 0
+            ? pick(rng, milestoneIds)
+            : null,
+        relatedMeetingId:
+          chance(rng, 0.15) && meetingIds.length > 0
+            ? pick(rng, meetingIds)
+            : null,
+        createdAt: now(),
+        updatedAt: now(),
+      }
+    );
+    ids.push(id);
+  }
+  return ids;
+}

services/AuthService.ts

@@ -92,6 +92,8 @@ export class AuthService {
       name: input.name,
       email: input.email,
       avatarUrl: input.avatarUrl,
+      theme: input.theme,
+      locale: input.locale,
     });
     if (!updated) {
       throw new NotFoundError('User', userId);

services/TodoService.ts

@@ -2,9 +2,16 @@ import { TodoRepository } from '@/repositories/TodoRepository';
 import { ProjectMemberRepository } from '@/repositories/ProjectMemberRepository';
 import { NotificationService } from '@/services/NotificationService';
 import { ActivityLogService } from '@/services/ActivityLogService';
+import { AttachmentService } from '@/services/AttachmentService';
 import { SseHub } from '@/lib/sse/hub';
+import type { SqliteDatabase } from '@/lib/db/sqlite';
 import { ForbiddenError, NotFoundError, ValidationError } from '@/lib/errors';
-import type { TodoColumn, TodoItem, TodoPriority } from '@/lib/types';
+import type {
+  AttachmentView,
+  TodoColumn,
+  TodoItem,
+  TodoPriority,
+} from '@/lib/types';
 
 const STANDARD_COLUMNS = ['Backlog', 'To Do', 'In Progress', 'Review', 'Done'];
 const VALID_PRIORITIES: TodoPriority[] = ['low', 'normal', 'high'];
@@ -15,7 +22,10 @@ export interface CreateItemInput {
   description?: string;
   assigneeId?: number | null;
   priority?: TodoPriority;
+  startDate?: string | null;
   dueDate?: string | null;
+  tags?: string | null;
+  fileIds?: number[];
 }
 
 export interface UpdateItemRequest {
@@ -23,16 +33,20 @@ export interface UpdateItemRequest {
   description?: string | null;
   assigneeId?: number | null;
   priority?: TodoPriority;
+  startDate?: string | null;
   dueDate?: string | null;
+  tags?: string | null;
   columnId?: number;
   orderIndex?: number;
   milestoneId?: number | null;
+  fileIds?: number[];
 }
 
 /**
  * ToDo/Kanbanの業務ロジックを担うService。
  * 標準カラム初期生成、権限チェック、タスクCRUD/移動/完了、
- * 担当者割当時の通知(todo_assigned)とアクティビティログ(todo_*)、SSE配信を行う。
+ * 担当者割当時の通知(todo_assigned)とアクティビティログ(todo_*)、
+ * 添付ファイル紐付け、SSE配信を行う。
  */
 export class TodoService {
   constructor(
@@ -40,7 +54,9 @@ export class TodoService {
     private readonly projectMemberRepository: ProjectMemberRepository,
     private readonly notificationService: NotificationService,
     private readonly activityLogService: ActivityLogService,
-    private readonly sseHub: SseHub
+    private readonly sseHub: SseHub,
+    private readonly attachmentService: AttachmentService,
+    private readonly db: SqliteDatabase
   ) {}
 
   getColumns(actorId: number, projectId: number): TodoColumn[] {
@@ -119,20 +135,33 @@ export class TodoService {
     if (input.priority && !VALID_PRIORITIES.includes(input.priority)) {
       throw new ValidationError('無効な優先度です', 'priority');
     }
-    const orderIndex =
-      input.columnId !== undefined
-        ? this.todoRepository.maxItemOrderIndex(input.columnId) + 1
-        : 0;
-    const item = this.todoRepository.createItem({
-      projectId,
-      columnId: input.columnId,
-      title: input.title,
-      creatorId: actorId,
-      description: input.description ?? null,
-      assigneeId: input.assigneeId ?? null,
-      priority: input.priority,
-      dueDate: input.dueDate ?? null,
-      orderIndex,
+    // タスク本体と添付紐付けはトランザクション内で一貫保存する
+    const item = this.db.transaction(() => {
+      const orderIndex =
+        this.todoRepository.maxItemOrderIndex(input.columnId) + 1;
+      const created = this.todoRepository.createItem({
+        projectId,
+        columnId: input.columnId,
+        title: input.title,
+        creatorId: actorId,
+        description: input.description ?? null,
+        assigneeId: input.assigneeId ?? null,
+        priority: input.priority,
+        startDate: input.startDate ?? null,
+        dueDate: input.dueDate ?? null,
+        tags: input.tags ?? null,
+        orderIndex,
+      });
+      if (input.fileIds && input.fileIds.length > 0) {
+        this.attachmentService.attach(
+          actorId,
+          projectId,
+          'todo_item',
+          created.id,
+          input.fileIds
+        );
+      }
+      return created;
     });
 
     if (input.assigneeId && input.assigneeId !== actorId) {
@@ -155,7 +184,19 @@ export class TodoService {
       throw new ValidationError('無効な優先度です', 'priority');
     }
     const previousAssignee = item.assigneeId;
-    const updated = this.todoRepository.updateItem(itemId, input);
+    const updated = this.db.transaction(() => {
+      const u = this.todoRepository.updateItem(itemId, input);
+      if (u && input.fileIds && input.fileIds.length > 0) {
+        this.attachmentService.attach(
+          actorId,
+          item.projectId,
+          'todo_item',
+          itemId,
+          input.fileIds
+        );
+      }
+      return u;
+    });
     if (!updated) throw new NotFoundError('TodoItem', itemId);
 
     if (
@@ -194,6 +235,45 @@ export class TodoService {
     return updated;
   }
 
+  /**
+   * 指定カラム内のアイテム順序を itemIds の順で再採番する。
+   * 同一カラムの並べ替えだけでなく、別カラムからの移動(対象カラムへの挿入)にも使う。
+   * すべて同一プロジェクト内であることを検証し、1トランザクションで更新する。
+   */
+  reorderItems(
+    actorId: number,
+    projectId: number,
+    columnId: number,
+    itemIds: number[]
+  ): TodoItem[] {
+    this.requireMember(projectId, actorId);
+    const column = this.todoRepository.findColumnById(columnId);
+    if (!column || column.projectId !== projectId) {
+      throw new NotFoundError('TodoColumn', columnId);
+    }
+    const ids = Array.isArray(itemIds) ? itemIds : [];
+    if (ids.length === 0) {
+      // 空の並べ替えは何も変更せず、SSE/ログも出さない
+      return this.todoRepository
+        .findItemsByProject(projectId)
+        .filter((i) => i.columnId === columnId);
+    }
+    this.db.transaction(() => {
+      ids.forEach((id, idx) => {
+        const item = this.todoRepository.findItemById(id);
+        if (!item || item.projectId !== projectId) {
+          throw new NotFoundError('TodoItem', id);
+        }
+        this.todoRepository.updateItem(id, { columnId, orderIndex: idx });
+      });
+    });
+    this.logTodo(projectId, actorId, 'todo_updated', ids[0]);
+    this.broadcastTodo(projectId);
+    return this.todoRepository
+      .findItemsByProject(projectId)
+      .filter((i) => i.columnId === columnId);
+  }
+
   toggleComplete(actorId: number, itemId: number): TodoItem {
     const item = this.todoRepository.findItemById(itemId);
     if (!item) throw new NotFoundError('TodoItem', itemId);
@@ -220,10 +300,29 @@ export class TodoService {
     if (item.creatorId !== actorId && role !== 'admin') {
       throw new ForbiddenError('作成者または管理者のみ削除できます');
     }
-    this.todoRepository.deleteItem(itemId);
+    this.db.transaction(() => {
+      this.attachmentService.detach('todo_item', itemId);
+      this.todoRepository.deleteItem(itemId);
+    });
     this.broadcastTodo(item.projectId);
   }
 
+  /** 単一のToDoアイテムを取得(メンバーシップチェック付き)。 */
+  getItem(actorId: number, itemId: number): TodoItem {
+    const item = this.todoRepository.findItemById(itemId);
+    if (!item) throw new NotFoundError('TodoItem', itemId);
+    this.requireMember(item.projectId, actorId);
+    return item;
+  }
+
+  /** ToDoに紐付く添付ファイル一覧を取得(メンバーシップチェック付き)。 */
+  getItemAttachments(actorId: number, itemId: number): AttachmentView[] {
+    const item = this.todoRepository.findItemById(itemId);
+    if (!item) throw new NotFoundError('TodoItem', itemId);
+    this.requireMember(item.projectId, actorId);
+    return this.attachmentService.listViews('todo_item', itemId);
+  }
+
   private requireMember(projectId: number, actorId: number): void {
     if (!this.projectMemberRepository.isMember(projectId, actorId)) {
       throw new ForbiddenError('プロジェクトに参加していません');

tailwind.config.ts

@@ -1,6 +1,7 @@
 import type { Config } from 'tailwindcss';
 
 const config: Config = {
+  darkMode: 'class',
   content: [
     './app/**/*.{js,ts,jsx,tsx,mdx}',
     './components/**/*.{js,ts,jsx,tsx,mdx}',