fix(admin): UX improvements — silent fetch failures, empty states, batch loading guards, dashboard refresh

- Replace console.error-only catches with message.error user-facing notifications
  across Bills, Classes, ClassroomRentals, ClassroomSchedule, Classrooms, Deposits,
  Expenses, OperationLogs, Permissions, Roles, RoomVisual, Rooms, Students,
  Tenants, Users
- Add Empty component via Table locale prop on list pages: Bills, Classes,
  ClassroomRentals, Classrooms, Deposits, Expenses (room+personal), Occupancies,
  Rooms, Students, Tenants, Roles
- Add batchLoading state to batch delete/update operations: Bills (batchDelete,
  batchUpdateStatus), Expenses (batchDeleteRoom, batchDeletePersonal),
  Occupancies (batchCheckOut, batchDelete), Rooms (batchDelete),
  Students (batchDelete)
- Add refreshLoading indicator to Dashboard header when re-fetching data
- Consistent error pattern: catch (e: unknown) { const err = e as { message?: string }; message.error(...); }

apps/admin/src/pages/Permissions/index.tsx

@@ -1,5 +1,5 @@
 import React, { useEffect, useState } from 'react';
-import { Card, Tag, Input, Space, Spin, Empty } from 'antd';
+import { Card, Tag, Input, Space, Spin, Empty, message } from 'antd';
 import api from '../../api';
 
 interface PermissionItem {
@@ -36,7 +36,10 @@ const PermissionsPage: React.FC = () => {
     api
       .get('/rbac/permissions/tree')
       .then((res: any) => setPermTree(res))
-      .catch(console.error)
+      .catch((e: unknown) => {
+        const err = e as { message?: string };
+        message.error(err?.message || '加载权限失败');
+      })
       .finally(() => setLoading(false));
   }, []);