feat(m6): board with threads/comments, markdown, tests, e2e

- BoardRepository (thread/comment CRUD, soft-delete, search, pagination,
  pinned-first ordering) + BoardService (membership permission,
  author/admin edit/delete, comment->board_commented notification,
  board_posted/comment_added activity logs, category validation)
- APIs: threads list/create/detail/edit/delete, comments create/edit/delete
- MarkdownBody (react-markdown + remark-gfm + rehype-sanitize),
  ThreadForm, CommentForm, board list + thread detail screens, ProjectNav link
- Unit tests (BoardRepository, BoardService) + e2e board.spec

app/api/projects/[projectId]/board/comments/[commentId]/route.ts

@@ -0,0 +1,51 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService } from '@/lib/api/services';
+import { UnauthorizedError } from '@/lib/errors';
+import { handleApiError, jsonError } from '@/lib/api/handleError';
+
+export const runtime = 'nodejs';
+
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; commentId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { commentId } = 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 service = createBoardService();
+  try {
+    const comment = service.updateComment(
+      user.id,
+      Number(commentId),
+      String(body.bodyMd ?? '')
+    );
+    return NextResponse.json({ comment });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}
+
+export async function DELETE(
+  _request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; commentId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { commentId } = await params;
+
+  const service = createBoardService();
+  try {
+    service.deleteComment(user.id, Number(commentId));
+    return NextResponse.json({ ok: true });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}

app/api/projects/[projectId]/board/threads/[threadId]/comments/route.ts

@@ -0,0 +1,34 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService } from '@/lib/api/services';
+import { UnauthorizedError } from '@/lib/errors';
+import { handleApiError, jsonError } from '@/lib/api/handleError';
+
+export const runtime = 'nodejs';
+
+export async function POST(
+  request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; threadId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { threadId } = 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 service = createBoardService();
+  try {
+    const comment = service.createComment(
+      user.id,
+      Number(threadId),
+      String(body.bodyMd ?? '')
+    );
+    return NextResponse.json({ comment }, { status: 201 });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}

app/api/projects/[projectId]/board/threads/[threadId]/route.ts

@@ -0,0 +1,75 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService } from '@/lib/api/services';
+import { UnauthorizedError } from '@/lib/errors';
+import { handleApiError, jsonError } from '@/lib/api/handleError';
+
+export const runtime = 'nodejs';
+
+export async function GET(
+  _request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; threadId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { threadId } = await params;
+
+  const service = createBoardService();
+  try {
+    const thread = service.getThread(user.id, Number(threadId));
+    const comments = service.listComments(user.id, Number(threadId));
+    return NextResponse.json({ thread, comments });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}
+
+export async function PATCH(
+  request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; threadId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { threadId } = 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 service = createBoardService();
+  try {
+    const thread = service.updateThread(user.id, Number(threadId), {
+      title: typeof body.title === 'string' ? body.title : undefined,
+      bodyMd: typeof body.bodyMd === 'string' ? body.bodyMd : undefined,
+      category:
+        typeof body.category === 'string'
+          ? (body.category as never)
+          : undefined,
+      isPinned: typeof body.isPinned === 'number' ? body.isPinned : undefined,
+      isImportant:
+        typeof body.isImportant === 'number' ? body.isImportant : undefined,
+    });
+    return NextResponse.json({ thread });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}
+
+export async function DELETE(
+  _request: NextRequest,
+  { params }: { params: Promise<{ projectId: string; threadId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { threadId } = await params;
+
+  const service = createBoardService();
+  try {
+    service.deleteThread(user.id, Number(threadId));
+    return NextResponse.json({ ok: true });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}

app/api/projects/[projectId]/board/threads/route.ts

@@ -0,0 +1,57 @@
+import { NextRequest, NextResponse } from 'next/server';
+import { getCurrentUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService } from '@/lib/api/services';
+import { UnauthorizedError } from '@/lib/errors';
+import { handleApiError, jsonError } from '@/lib/api/handleError';
+
+export const runtime = 'nodejs';
+
+export async function GET(
+  request: NextRequest,
+  { params }: { params: Promise<{ projectId: string }> }
+) {
+  const user = await getCurrentUser();
+  if (!user) return handleApiError(new UnauthorizedError());
+  const { projectId } = await params;
+  const page = Number(request.nextUrl.searchParams.get('page') ?? '1') || 1;
+  const search = request.nextUrl.searchParams.get('q') ?? undefined;
+
+  const service = createBoardService();
+  try {
+    return NextResponse.json(
+      service.listThreads(user.id, Number(projectId), { page, search })
+    );
+  } catch (error) {
+    return handleApiError(error);
+  }
+}
+
+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 service = createBoardService();
+  try {
+    const thread = service.createThread(user.id, Number(projectId), {
+      title: String(body.title ?? ''),
+      bodyMd: String(body.bodyMd ?? ''),
+      category:
+        typeof body.category === 'string'
+          ? (body.category as never)
+          : undefined,
+    });
+    return NextResponse.json({ thread }, { status: 201 });
+  } catch (error) {
+    return handleApiError(error);
+  }
+}

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

@@ -0,0 +1,78 @@
+import { redirect } from 'next/navigation';
+import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService } from '@/lib/api/services';
+import { Header } from '@/components/layout/Header';
+import { ProjectNav } from '@/components/layout/ProjectNav';
+import { MarkdownBody } from '@/components/board/MarkdownBody';
+import { CommentForm } from '@/components/board/CommentForm';
+import { ForbiddenError, NotFoundError } from '@/lib/errors';
+
+export const dynamic = 'force-dynamic';
+
+export default async function ThreadDetailPage({
+  params,
+}: {
+  params: Promise<{ projectId: string; threadId: string }>;
+}) {
+  const user = await getCurrentUser();
+  if (!user) redirect('/login');
+  const { projectId, threadId } = await params;
+
+  const boardService = createBoardService();
+  let thread;
+  let comments;
+  try {
+    thread = boardService.getThread(user.id, Number(threadId));
+    comments = boardService.listComments(user.id, Number(threadId));
+  } catch (error) {
+    if (error instanceof ForbiddenError || error instanceof NotFoundError) {
+      redirect(`/projects/${projectId}/board`);
+    }
+    throw error;
+  }
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Header user={toPublicUser(user)} />
+      <ProjectNav projectId={Number(projectId)} active="board" />
+      <main className="mx-auto max-w-3xl space-y-6 p-6">
+        <a
+          href={`/projects/${projectId}/board`}
+          className="text-sm text-blue-600 hover:underline"
+        >
+          ← 掲示板一覧へ
+        </a>
+        <div className="rounded-lg border bg-white 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">
+                {thread.category}
+              </span>
+            )}
+          </div>
+          <div className="mt-4">
+            <MarkdownBody bodyMd={thread.bodyMd} />
+          </div>
+          <p className="mt-4 text-xs text-gray-400">
+            投稿: {thread.createdAt} / 更新: {thread.updatedAt}
+          </p>
+        </div>
+
+        <section className="space-y-4">
+          <h2 className="text-lg font-bold">コメント ({comments.total})</h2>
+          {comments.items.map((comment) => (
+            <div
+              key={comment.id}
+              className="rounded-lg border bg-white p-4 shadow-sm"
+            >
+              <MarkdownBody bodyMd={comment.bodyMd} />
+              <p className="mt-2 text-xs text-gray-400">{comment.createdAt}</p>
+            </div>
+          ))}
+          <CommentForm projectId={Number(projectId)} threadId={thread.id} />
+        </section>
+      </main>
+    </div>
+  );
+}

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

@@ -0,0 +1,77 @@
+import { redirect } from 'next/navigation';
+import { getCurrentUser, toPublicUser } from '@/lib/auth/getCurrentUser';
+import { createBoardService, createProjectService } from '@/lib/api/services';
+import { Header } from '@/components/layout/Header';
+import { ProjectNav } from '@/components/layout/ProjectNav';
+import { ThreadForm } from '@/components/board/ThreadForm';
+import { ForbiddenError, NotFoundError } from '@/lib/errors';
+
+export const dynamic = 'force-dynamic';
+
+export default async function BoardPage({
+  params,
+  searchParams,
+}: {
+  params: Promise<{ projectId: string }>;
+  searchParams: Promise<{ q?: string; page?: string }>;
+}) {
+  const user = await getCurrentUser();
+  if (!user) redirect('/login');
+  const { projectId } = await params;
+  const { q, page } = await searchParams;
+
+  const projectService = createProjectService();
+  let project: Awaited<ReturnType<typeof projectService.getProject>>;
+  try {
+    project = projectService.getProject(user.id, Number(projectId));
+  } catch (error) {
+    if (error instanceof ForbiddenError || error instanceof NotFoundError) {
+      redirect('/dashboard');
+    }
+    throw error;
+  }
+
+  const boardService = createBoardService();
+  const { items } = boardService.listThreads(user.id, project.id, {
+    page: Number(page ?? '1') || 1,
+    search: q,
+  });
+
+  return (
+    <div className="min-h-screen bg-gray-50">
+      <Header user={toPublicUser(user)} />
+      <ProjectNav projectId={project.id} active="board" />
+      <main className="mx-auto max-w-3xl space-y-6 p-6">
+        <h1 className="text-2xl font-bold">掲示板</h1>
+        <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>
+          ) : (
+            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"
+              >
+                <div className="flex items-center justify-between">
+                  <h3 className="font-semibold text-gray-800">
+                    {thread.isPinned === 1 && '📌 '}
+                    {thread.isImportant === 1 && '❗ '}
+                    {thread.title}
+                  </h3>
+                  {thread.category && (
+                    <span className="rounded bg-gray-100 px-2 py-0.5 text-xs">
+                      {thread.category}
+                    </span>
+                  )}
+                </div>
+                <p className="mt-1 text-xs text-gray-400">{thread.createdAt}</p>
+              </a>
+            ))
+          )}
+        </section>
+      </main>
+    </div>
+  );
+}