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>

tsconfig.json

@@ -52,5 +52,13 @@
     "components",
     "eslint.config.ts"
   ],
-  "exclude": ["node_modules", ".wxt"]
+  "exclude": [
+    "node_modules",
+    ".wxt",
+    "components/__tests__",
+    "**/*.test.tsx",
+    "**/*.test.ts",
+    "vitest.config.ts",
+    "vitest.setup.ts"
+  ]
 }