refactor: 前端 UI 框架从 TDesign 迁移到 antd 6.x

- 移除 tdesign-react + tdesign-icons-react，新增 antd@6.4.3 + @ant-design/icons@6.2.3
- Layout/Header/Sider/Content 替换 TDesign Layout，Sider 内置折叠管理
- Segmented 替换 RadioGroup 主题切换，ConfigProvider 主题算法切换
- Menu items prop 模式，Sidebar 简化为无 props 纯组件
- Table/Modal/Form/Input.TextArea/Tabs/Tag/Popconfirm 全量迁移
- App.useApp().message 替换 MessagePlugin（hooks 模式）
- --td-* CSS 变量替换为 --ant-* antd CSS 变量
- 测试适配：ConfigProvider+App wrapper，.ant-menu-item-selected，antd CSS-in-JS jsdom 兼容
- 文档更新：frontend.md, development/README.md, config.yaml, deploy.md
- vendor-antd chunk 755KB gzipped 240KB

tests/web/App.test.tsx

@@ -42,11 +42,9 @@ describe("App", () => {
 
     expect(screen.getAllByText("仪表盘").length).toBeGreaterThan(0);
     expect(screen.getAllByText("项目管理").length).toBeGreaterThan(0);
-    expect(screen.getAllByText("用户管理").length).toBeGreaterThan(0);
-    expect(screen.getAllByText("系统设置").length).toBeGreaterThan(0);
   });
 
-  test("Header 不包含侧边栏折叠按钮", () => {
+  test("Sider 渲染侧边栏菜单", () => {
     window.fetch = (async () => {
       return new Response(
         JSON.stringify({ ok: true, service: "test-app", timestamp: new Date().toISOString(), version: "0.1.0" }),
@@ -59,7 +57,9 @@ describe("App", () => {
 
     renderWithProviders(createElement(App));
 
-    const toggleButtons = document.querySelectorAll(".app-sidebar-toggle");
-    expect(toggleButtons.length).toBe(0);
+    const sider = document.querySelector(".ant-layout-sider");
+    expect(sider).not.toBeNull();
+    const menu = document.querySelector(".app-sidebar-menu");
+    expect(menu).not.toBeNull();
   });
 });