feat(account-management): optimize account loading with async validation

- Add new /getAccounts API for fast account retrieval without validation
- Update frontend to use fast API for initial load, showing accounts immediately
- Add '验证中' status with loading animation to indicate validation progress
- Implement background validation process that doesn't block UI
- Add Loading icon from Element Plus for visual feedback during validation
- Update status display logic to handle '验证中', '正常', and invalid states
- Improve user experience with immediate feedback and async validation

sau_frontend/src/api/account.js

@@ -2,21 +2,26 @@ import { http } from '@/utils/request'
 
 // 账号管理相关API
 export const accountApi = {
-  // 获取有效账号列表
+  // 获取有效账号列表（带验证）
   getValidAccounts() {
     return http.get('/getValidAccounts')
   },
-  
+
+  // 获取账号列表（不带验证，快速加载）
+  getAccounts() {
+    return http.get('/getAccounts')
+  },
+
   // 添加账号
   addAccount(data) {
     return http.post('/account', data)
   },
-  
+
   // 更新账号
   updateAccount(data) {
     return http.post('/updateUserinfo', data)
   },
-  
+
   // 删除账号
   deleteAccount(id) {
     return http.get(`/deleteAccount?id=${id}`)