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/test-utils.tsx

@@ -1,7 +1,10 @@
+import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { render } from "@testing-library/react";
 import { mock } from "bun:test";
+import { createElement, StrictMode } from "react";
+import { MemoryRouter } from "react-router";
 
-// Note: jsdom and polyfills are now set up in tests/setup.ts
-// This file only contains component-specific mocks
+import { ErrorBoundary } from "../../src/web/components/ErrorBoundary";
 
 // Mock recharts BEFORE any component imports
 void mock.module("recharts", () => ({
@@ -15,6 +18,42 @@ void mock.module("recharts", () => ({
   YAxis: () => null,
 }));
 
+export interface RenderWithProvidersOptions {
+  initialRoute?: string;
+}
+
+export function renderWithProviders(ui: React.ReactElement, options?: RenderWithProvidersOptions) {
+  const queryClient = createTestQueryClient();
+  const initialRoute = options?.initialRoute ?? "/";
+
+  return render(
+    createElement(
+      StrictMode,
+      null,
+      createElement(
+        ErrorBoundary,
+        null,
+        createElement(
+          QueryClientProvider,
+          { client: queryClient },
+          createElement(MemoryRouter, { initialEntries: [initialRoute] }, ui),
+        ),
+      ),
+    ),
+  );
+}
+
+function createTestQueryClient() {
+  return new QueryClient({
+    defaultOptions: {
+      queries: {
+        retry: false,
+        staleTime: 0,
+      },
+    },
+  });
+}
+
 // Custom test helpers (替代 jest-dom matchers)
 export const testHelpers = {
   toBeInTheDocument: (element: Element | null) => {