feat(miniprogram): 适老化修复 — Phase 2e

M6: 创建 utils/date.ts 统一日期工具函数（formatDate/formatDateTime/toRelativeDate 等）
M8: 28 个 SCSS 文件 font-size 20px → 22px 全量适老化
M7: request.ts 增加 403 权限不足/5xx 服务器错误/网络超时异常统一拦截

apps/miniprogram/src/services/request.ts

@@ -60,7 +60,18 @@ async function doRefresh(): Promise<boolean> {
 async function request<T>(method: string, path: string, data?: unknown): Promise<T> {
   const headers = await getHeaders();
   const url = `${BASE_URL}${path}`;
-  const res = await Taro.request({ url, method: method as any, data, header: headers, timeout: 15000 });
+  let res: Taro.request.SuccessCallbackResult;
+  try {
+    res = await Taro.request({ url, method: method as any, data, header: headers, timeout: 15000 });
+  } catch (err: any) {
+    const msg = err?.errMsg || '';
+    if (msg.includes('timeout')) {
+      Taro.showToast({ title: '网络超时，请重试', icon: 'none' });
+      throw new Error('网络超时');
+    }
+    Taro.showToast({ title: '网络异常，请检查连接', icon: 'none' });
+    throw new Error('网络异常');
+  }
 
   if (res.statusCode === 401) {
     const refreshed = await tryRefreshToken();
@@ -73,6 +84,16 @@ async function request<T>(method: string, path: string, data?: unknown): Promise
     throw new Error('登录已过期');
   }
 
+  if (res.statusCode === 403) {
+    Taro.showToast({ title: '权限不足', icon: 'none' });
+    throw new Error('权限不足');
+  }
+
+  if (res.statusCode >= 500) {
+    Taro.showToast({ title: '服务器繁忙，请稍后重试', icon: 'none' });
+    throw new Error('服务器错误');
+  }
+
   const body = res.data as ApiResponse<T>;
   if (!body.success) throw new Error(body.message || '请求失败');
   return body.data as T;