feat(schedules): implement frontend schedule week view page

- Create SchedulesPage with week selector, classroom/class filters
- Matrix: rows=classrooms, cols=Mon-Sun, cells show subject/teacher/time
- Click empty cell -> create modal with schedule form
- Click occupied cell -> detail modal with delete button
- Conflict: backend 409/400 -> message.error with conflict info
- Route /schedules with PermissionRoute (schedule:view)
- Menu item '排课管理' with CalendarOutlined icon

apps/admin/src/App.tsx

@@ -20,6 +20,7 @@ import ClassDetailPage from './pages/Classes/detail';
 import TenantsPage from './pages/Tenants';
 import ClassroomRentalsPage from './pages/ClassroomRentals';
 import ClassroomSchedulePage from './pages/ClassroomSchedule';
+import SchedulesPage from './pages/Schedules';
 import RolesPage from './pages/Roles';
 import PermissionsPage from './pages/Permissions';
 import PermissionRoute from './components/PermissionRoute';
@@ -200,6 +201,15 @@ const App: React.FC = () => {
                   </PermissionRoute>
                 }
               />
+
+              <Route
+                path="schedules"
+                element={
+                  <PermissionRoute permission="schedule:view">
+                    <SchedulesPage />
+                  </PermissionRoute>
+                }
+              />
             </Route>
           </Routes>
         </BrowserRouter>