feat(web): Q3 前端体验优化 — ErrorBoundary + 5 hooks + 共享类型 + i18n 基础

- ErrorBoundary 组件：全局错误捕获与优雅降级
- 提取 5 个自定义 hooks：useCountUp, useDarkMode, useDebouncedValue, usePaginatedData, useApiRequest
- 从 11 个 API 文件提取 PaginatedResponse 共享类型到 api/types.ts
- 统一 API 错误处理（api/errors.ts）
- client.ts 迁移到 axios adapter 模式（替代废弃的 CancelToken）
- 添加 react-i18next 国际化基础设施 + zh-CN 语言包

apps/web/src/api/client.ts

@@ -1,11 +1,5 @@
 import axios from 'axios';
 
-const client = axios.create({
-  baseURL: '/api/v1',
-  timeout: 10000,
-  headers: { 'Content-Type': 'application/json' },
-});
-
 // 请求缓存：短时间内相同请求复用结果
 interface CacheEntry {
   data: unknown;
@@ -19,25 +13,38 @@ function getCacheKey(config: { url?: string; params?: unknown; method?: string }
   return `${config.method || 'get'}:${config.url || ''}:${JSON.stringify(config.params || {})}`;
 }
 
-// Request interceptor: attach access token + cache
+const defaultAdapter = axios.getAdapter(axios.defaults.adapter);
+
+const client = axios.create({
+  baseURL: '/api/v1',
+  timeout: 10000,
+  headers: { 'Content-Type': 'application/json' },
+  adapter: (config) => {
+    // GET 请求检查缓存
+    if (config.method === 'get' && config.url) {
+      const key = getCacheKey(config);
+      const entry = requestCache.get(key);
+      if (entry && Date.now() - entry.timestamp < CACHE_TTL) {
+        return Promise.resolve({
+          data: entry.data,
+          status: 200,
+          statusText: 'OK (cached)',
+          headers: {} as any,
+          config,
+        });
+      }
+    }
+    return defaultAdapter(config);
+  },
+});
+
+// Request interceptor: attach access token
 client.interceptors.request.use((config) => {
   const token = localStorage.getItem('access_token');
   if (token) {
     config.headers.Authorization = `Bearer ${token}`;
   }
 
-  // GET 请求检查缓存
-  if (config.method === 'get' && config.url) {
-    const key = getCacheKey(config);
-    const entry = requestCache.get(key);
-    if (entry && Date.now() - entry.timestamp < CACHE_TTL) {
-      const source = axios.CancelToken.source();
-      config.cancelToken = source.token;
-      // 通过适配器返回缓存数据
-      source.cancel(JSON.stringify({ __cached: true, data: entry.data }));
-    }
-  }
-
   return config;
 });
 
@@ -52,14 +59,6 @@ client.interceptors.response.use(
     return response;
   },
   async (error) => {
-    // 处理缓存命中
-    if (axios.isCancel(error)) {
-      const cached = JSON.parse(error.message || '{}');
-      if (cached.__cached) {
-        return { data: cached.data, status: 200, statusText: 'OK (cached)', headers: {}, config: {} };
-      }
-    }
-
     const originalRequest = error.config;
     if (error.response?.status === 401 && !originalRequest._retry) {
       if (isRefreshing) {