feat: 完成前端重构，采用 Ant Design 5 和完整测试体系

- 采用 Ant Design 5 作为 UI 组件库，替换自定义组件
- 集成 React Router v7 提供路由导航
- 使用 TanStack Query v5 管理数据获取和缓存
- 建立 Vitest + React Testing Library 测试体系
- 添加 Playwright E2E 测试覆盖
- 使用 MSW mock API 响应
- 配置 TypeScript strict 模式
- 采用 SCSS Modules 组织样式
- 更新 OpenSpec 规格以反映前端架构变更
- 归档 frontend-refactor 变更记录

frontend/src/__tests__/setup.ts

@@ -0,0 +1,26 @@
+import '@testing-library/jest-dom/vitest';
+
+// Polyfill window.matchMedia for jsdom (required by antd)
+Object.defineProperty(window, 'matchMedia', {
+  writable: true,
+  value: (query: string) => ({
+    matches: false,
+    media: query,
+    onchange: null,
+    addListener: () => {},
+    removeListener: () => {},
+    addEventListener: () => {},
+    removeEventListener: () => {},
+    dispatchEvent: () => false,
+  }),
+});
+
+// Polyfill window.getComputedStyle to suppress jsdom warnings
+const originalGetComputedStyle = window.getComputedStyle;
+window.getComputedStyle = (elt: Element, pseudoElt?: string | null) => {
+  try {
+    return originalGetComputedStyle(elt, pseudoElt);
+  } catch {
+    return {} as CSSStyleDeclaration;
+  }
+};