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/Classrooms/index.tsx

@@ -13,6 +13,7 @@ import {
   Popconfirm,
   Upload,
   Tooltip,
+  Empty,
 } from 'antd';
 import {
   PlusOutlined,
@@ -69,8 +70,8 @@ const ClassroomsPage: React.FC = () => {
     try {
       const res: any = await api.get('/classrooms', { params: { includeArchived: showArchived } });
       setData(res);
-    } catch (e) {
-      console.error(e);
+    } catch (e: any) {
+      message.error(e?.message || '加载失败，请稍后重试');
     }
     setLoading(false);
   };
@@ -287,9 +288,9 @@ const ClassroomsPage: React.FC = () => {
         dataSource={filteredData}
         rowKey="id"
         loading={loading}
+        locale={{ emptyText: <Empty description="暂无数据" /> }}
         pagination={{ pageSize: 20, showTotal: (total) => `共 ${total} 条` }}
       />
-
       <Modal
         title={editing ? '编辑教室' : '添加教室'}
         open={modalOpen}