feat(seed): ~5x richer demo data via deterministic generators

Rewrite scripts/seed-demo.ts as a thin orchestrator over a new scripts/seed/ module (rng, pools, helpers, content, schedule, logs, generators). Scales demo data from 6 users/3 projects to ~30 users/15 projects with ~5-8x per-table content (~6.8x total rows) via a seeded mulberry32 PRNG for full reproducibility (incl. bcrypt salts and file/URL identifiers). FK-safe ordering, real captured IDs for activity logs, enum pools typed against lib/types. Preserves canonical login credentials and projects.

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(),
+      }
+    );
+  }
+}