feat: 重构前端为企业 Admin 后台布局，引入 React Router 路由

- 引入 React Router v7 (Declarative mode) 实现 SPA 路由
- 重构 Layout 为 Header + 侧边栏 + 内容区的企业 Admin 布局
- 新增侧边栏菜单组件，支持折叠/展开，状态持久化到 localStorage
- 新增示例页面：仪表盘、用户管理、系统设置、404
- 菜单配置与路由统一为单一数据源 (menu.tsx)
- Vite code splitting 新增 vendor-router 组
- 更新 DEVELOPMENT.md 和 README.md 文档

tests/web/App.test.tsx

@@ -1,43 +1,14 @@
 /* eslint-disable @typescript-eslint/require-await */
-import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
-import { render, screen } from "@testing-library/react";
+import { screen } from "@testing-library/react";
 import { describe, expect, test } from "bun:test";
-import { createElement, StrictMode } from "react";
+import { createElement } from "react";
 
 import { APP } from "../../src/shared/app";
 import { App } from "../../src/web/app";
-import { ErrorBoundary } from "../../src/web/components/ErrorBoundary";
-
-function createTestQueryClient() {
-  return new QueryClient({
-    defaultOptions: {
-      queries: {
-        retry: false,
-        staleTime: 0,
-      },
-    },
-  });
-}
-
-function renderApp() {
-  const queryClient = createTestQueryClient();
-
-  return render(
-    createElement(
-      StrictMode,
-      null,
-      createElement(
-        ErrorBoundary,
-        null,
-        createElement(QueryClientProvider, { client: queryClient }, createElement(App)),
-      ),
-    ),
-  );
-}
+import { renderWithProviders } from "./test-utils";
 
 describe("App", () => {
   test("渲染 Layout 骨架和品牌名", () => {
-    // mock /health fetch 避免网络错误
     window.fetch = (async () => {
       return new Response(JSON.stringify({ ok: true, service: "test-app", timestamp: new Date().toISOString() }), {
         headers: { "Content-Type": "application/json" },
@@ -45,11 +16,26 @@ describe("App", () => {
       });
     }) as unknown as typeof fetch;
 
-    renderApp();
+    renderWithProviders(createElement(App));
 
     expect(screen.getByText(APP.title)).not.toBeNull();
     expect(screen.getByText("系统")).not.toBeNull();
     expect(screen.getByText("明亮")).not.toBeNull();
     expect(screen.getByText("黑暗")).not.toBeNull();
   });
+
+  test("渲染侧边栏菜单项", () => {
+    window.fetch = (async () => {
+      return new Response(JSON.stringify({ ok: true, service: "test-app", timestamp: new Date().toISOString() }), {
+        headers: { "Content-Type": "application/json" },
+        status: 200,
+      });
+    }) as unknown as typeof fetch;
+
+    renderWithProviders(createElement(App));
+
+    expect(screen.getAllByText("仪表盘").length).toBeGreaterThan(0);
+    expect(screen.getAllByText("用户管理").length).toBeGreaterThan(0);
+    expect(screen.getAllByText("系统设置").length).toBeGreaterThan(0);
+  });
 });