feat: deliver P2 v0.2.0 with unified editor, search, and snapshots

Implement schema v2 migration, outline/setting/inspiration CRUD, unified TipTap editing, reference panel with mentions, FTS global search, chapter version history, writing landmarks, word frequency analysis, light theme contrast fixes, and full unit/E2E test coverage.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/main/db/repositories/snapshot.repo.ts

@@ -0,0 +1,81 @@
+import { randomUUID } from 'crypto'
+import type { Snapshot, SnapshotType } from '../../../shared/types'
+import type { SqliteDb } from '../types'
+
+function mapRow(row: Record<string, unknown>): Snapshot {
+  return {
+    id: row.id as string,
+    chapterId: row.chapter_id as string,
+    type: row.type as SnapshotType,
+    name: (row.name as string) ?? '',
+    content: row.content as string,
+    createdAt: row.created_at as string
+  }
+}
+
+export class SnapshotRepository {
+  constructor(private db: SqliteDb) {}
+
+  create(chapterId: string, type: SnapshotType, content: string, name = ''): Snapshot {
+    const id = randomUUID()
+    this.db
+      .prepare(`INSERT INTO snapshots (id, chapter_id, type, name, content) VALUES (?, ?, ?, ?, ?)`)
+      .run(id, chapterId, type, name, content)
+    return this.get(id)!
+  }
+
+  get(id: string): Snapshot | null {
+    const row = this.db.prepare('SELECT * FROM snapshots WHERE id = ?').get(id) as
+      | Record<string, unknown>
+      | undefined
+    return row ? mapRow(row) : null
+  }
+
+  list(chapterId: string): Snapshot[] {
+    return (
+      this.db
+        .prepare('SELECT * FROM snapshots WHERE chapter_id = ? ORDER BY created_at DESC')
+        .all(chapterId) as Record<string, unknown>[]
+    ).map(mapRow)
+  }
+
+  delete(id: string): void {
+    this.db.prepare('DELETE FROM snapshots WHERE id = ?').run(id)
+  }
+
+  pruneAuto(chapterId: string, max: number): void {
+    const autos = (
+      this.db
+        .prepare(
+          `SELECT id FROM snapshots WHERE chapter_id = ? AND type = 'auto' ORDER BY created_at ASC`
+        )
+        .all(chapterId) as { id: string }[]
+    )
+    const excess = autos.length - max
+    if (excess <= 0) return
+    for (let i = 0; i < excess; i++) {
+      this.delete(autos[i].id)
+    }
+  }
+
+  prunePersist(chapterId: string, max: number): void {
+    const items = (
+      this.db
+        .prepare(
+          `SELECT id FROM snapshots WHERE chapter_id = ? AND type = 'persist' ORDER BY created_at ASC`
+        )
+        .all(chapterId) as { id: string }[]
+    )
+    const excess = items.length - max
+    if (excess <= 0) return
+    for (let i = 0; i < excess; i++) {
+      this.delete(items[i].id)
+    }
+  }
+
+  restore(snapshotId: string): string {
+    const snap = this.get(snapshotId)
+    if (!snap) throw new Error('Snapshot not found')
+    return snap.content
+  }
+}