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/Dashboard/index.tsx

@@ -83,13 +83,19 @@ const DashboardPage: React.FC = () => {
   const [roomRanking, setRoomRanking] = useState<Array<{ roomNumber: string; total: string }>>([]);
   const [classroomUtil, setClassroomUtil] = useState<ClassroomUtilStats | null>(null);
   const [loading, setLoading] = useState(true);
+  const [refreshLoading, setRefreshLoading] = useState(false);
   const [period, setPeriod] = useState<[string, string]>([
     dayjs().startOf('month').format('YYYY-MM-DD'),
     dayjs().endOf('month').format('YYYY-MM-DD'),
   ]);
 
   const fetchData = useCallback(async () => {
-    setLoading(true);
+    const isRefresh = stats !== null;
+    if (isRefresh) {
+      setRefreshLoading(true);
+    } else {
+      setLoading(true);
+    }
     try {
       const [s, rr, cr, g] = await Promise.all([
         api.get<DashboardStats>('/dashboard/stats'),
@@ -114,7 +120,8 @@ const DashboardPage: React.FC = () => {
       message.error('数据加载失败，请稍后重试');
     }
     setLoading(false);
-  }, [period]);
+    setRefreshLoading(false);
+  }, [period, stats]);
 
   useEffect(() => {
     fetchData();
@@ -321,7 +328,7 @@ const DashboardPage: React.FC = () => {
           gap: 12,
         }}
       >
-        <h2 style={{ margin: 0 }}>数据面板</h2>
+        <h2 style={{ margin: 0 }}>数据面板{refreshLoading && <Spin size="small" style={{ marginLeft: 12 }} />}</h2>
         <RangePicker
           aria-label="选择日期范围"
           value={[dayjs(period[0]), dayjs(period[1])]}