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/layouts/MainLayout.tsx

@@ -77,6 +77,7 @@ const allMenuItems: MenuItemType[] = [
       { key: '/tenants', icon: <TagsOutlined />, label: '租赁方', permission: 'tenant:view' },
     ],
   },
+  { key: '/schedules', icon: <CalendarOutlined />, label: '排课管理', permission: 'schedule:view' },
   { key: '/operation-logs', icon: <AuditOutlined />, label: '操作日志', permission: 'log:view' },
   { key: '/roles', icon: <SafetyOutlined />, label: '角色管理', permission: 'role:view' },
   { key: '/permissions', icon: <KeyOutlined />, label: '权限一览', permission: 'role:view' },