feat: 实现笔临 P0/P1 Electron 桌面应用 v0.1.0

交付写作核心（TipTap、自动保存、分卷分章）、Onboarding、7 主题与双语 i18n、快捷键设置；主进程使用 node:sqlite；补全 Vitest 与 Playwright E2E；统一 design/ 目录并移除 desigin 拼写错误路径。

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

src/main/db/migrate.ts

@@ -0,0 +1,22 @@
+import type { SqliteDb } from './types'
+import schemaV1 from './schema-v1.sql?raw'
+
+const CURRENT_VERSION = 1
+
+export function migrate(db: SqliteDb): void {
+  db.exec(`CREATE TABLE IF NOT EXISTS schema_version (
+    version INTEGER PRIMARY KEY,
+    applied_at TEXT NOT NULL DEFAULT (datetime('now')),
+    description TEXT
+  )`)
+
+  const row = db.prepare('SELECT MAX(version) AS v FROM schema_version').get() as { v: number | null }
+  const current = row?.v ?? 0
+  if (current >= CURRENT_VERSION) return
+
+  db.exec(schemaV1)
+  db.prepare('INSERT INTO schema_version (version, description) VALUES (?, ?)').run(
+    CURRENT_VERSION,
+    'initial schema'
+  )
+}