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>

tests/main/wordfreq.service.test.ts

@@ -0,0 +1,41 @@
+import { describe, it, expect, beforeEach, afterEach } from 'vitest'
+import { DatabaseSync } from 'node:sqlite'
+import { migrate } from '../../src/main/db/migrate'
+import { VolumeRepository } from '../../src/main/db/repositories/volume.repo'
+import { ChapterRepository } from '../../src/main/db/repositories/chapter.repo'
+import { wordFreqService } from '../../src/main/services/wordfreq.service'
+import type { SqliteDb } from '../../src/main/db/types'
+
+describe('WordFreqService', () => {
+  let db: SqliteDb
+
+  beforeEach(() => {
+    db = new DatabaseSync(':memory:')
+    migrate(db)
+    const vol = new VolumeRepository(db).create('卷一', 0)
+    new ChapterRepository(db).create(
+      vol.id,
+      '第一章',
+      0,
+      '<p>林远走进青云山。The hero walked slowly.</p>'
+    )
+  })
+
+  afterEach(() => {
+    db.close()
+  })
+
+  it('counts CJK characters and latin words', () => {
+    const result = wordFreqService.analyze(db, { kind: 'book' })
+    expect(result.words.length).toBeGreaterThan(0)
+    const tokens = result.words.map((w) => w.token)
+    expect(tokens).toContain('林')
+    expect(tokens).toContain('the')
+  })
+
+  it('analyzes single chapter scope', () => {
+    const ch = (db.prepare('SELECT id FROM chapters LIMIT 1').get() as { id: string }).id
+    const result = wordFreqService.analyze(db, { kind: 'chapter', chapterId: ch })
+    expect(result.words.length).toBeGreaterThan(0)
+  })
+})