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>

components/__tests__/Navbar.test.tsx

@@ -0,0 +1,47 @@
+import { render, screen } from '@testing-library/react';
+import { MemoryRouter } from 'react-router-dom';
+import Navbar from '../Navbar';
+import { vi } from 'vitest';
+
+const mockItems = [
+  { path: '/', label: '首页', element: <div>首页</div> },
+  { path: '/timestamp', label: '时间戳', element: <div>时间戳</div> },
+];
+
+const renderWithRouter = (initialPath = '/', items = mockItems) => {
+  return render(
+    <MemoryRouter initialEntries={[initialPath]}>
+      <Navbar items={items} />
+    </MemoryRouter>,
+  );
+};
+
+describe('Navbar', () => {
+  beforeEach(() => {
+    // 模拟 useMediaQuery 以确保大屏幕行为
+    Object.defineProperty(window, 'matchMedia', {
+      writable: true,
+      value: vi.fn().mockImplementation((query) => ({
+        matches: query === '(min-width:768px)',
+        addEventListener: vi.fn(),
+        removeEventListener: vi.fn(),
+      })),
+    });
+  });
+
+  it('应该正确渲染所有导航项（大屏幕）', () => {
+    renderWithRouter();
+    mockItems.forEach((item) => {
+      expect(screen.getByText(item.label)).toBeInTheDocument();
+    });
+  });
+
+  it('没有提供 items 时应该正常渲染', () => {
+    render(
+      <MemoryRouter>
+        <Navbar />
+      </MemoryRouter>,
+    );
+    expect(true).toBe(true);
+  });
+});