refactor: 优化组件并添加测试覆盖

- 创建 CLAUDE.md 项目开发指导文档
- 提取公共常量到 components/constants.ts
- 修复 TimestampToDatetime 重复插件扩展问题
- 修复 DatetimeToTimestamp 时区解析问题
- 优化 RoutePersistence 移除不必要依赖
- 添加 Vitest 测试框架配置
- 为所有组件编写单元测试 (16个测试用例)
- 更新 .gitignore 忽略测试结果目录

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

package.json

@@ -14,7 +14,10 @@
     "compile": "tsc --noEmit",
     "postinstall": "wxt prepare",
     "prepare": "husky",
-    "lint": "eslint . --max-warnings=0"
+    "lint": "eslint . --max-warnings=0",
+    "test": "vitest run",
+    "test:watch": "vitest",
+    "test:coverage": "vitest run --coverage"
   },
   "dependencies": {
     "@emotion/react": "^11.14.0",
@@ -49,17 +52,20 @@
     "@types/webextension-polyfill": "^0.12.4",
     "@typescript-eslint/eslint-plugin": "^8.54.0",
     "@typescript-eslint/parser": "^8.54.0",
+    "@vitejs/plugin-react": "^6.0.1",
     "@wxt-dev/module-react": "^1.1.5",
     "eslint": "^9.39.2",
     "eslint-plugin-react": "^7.37.5",
     "eslint-plugin-react-hooks": "^7.0.1",
     "globals": "^17.2.0",
     "husky": "^9.1.7",
+    "jsdom": "^29.0.0",
     "lint-staged": "^16.2.7",
     "prettier": "^3.8.1",
     "terser": "^5.46.0",
     "typescript": "^5.9.3",
     "typescript-eslint": "^8.54.0",
+    "vitest": "^4.1.0",
     "wxt": "^0.20.6"
   }
 }