fix(my-classes): add selectedInstituteId to fetch dependency, silence unhandled rejection

Re-fetch classes when NeoInstitute context changes. Catch fetchMyClasses rejection with
logger.warn so unhandled promise rejections don't break the component boundary silently.
Use CircularProgress (MUI) for loading skeleton.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/pages/timetable/MyClassesPage.tsx

@@ -3,9 +3,19 @@ import { Link } from 'react-router-dom';
 import { AccessTime, KeyboardArrowRight, MenuBook, People, School } from '@mui/icons-material';
 import useTimetableStore from '../../stores/timetableStore';
 import { useUser } from '../../contexts/UserContext';
+import { useNeoInstitute } from '../../contexts/NeoInstituteContext';
+import { CircularProgress } from '@mui/material';
+import { logger } from '../../debugConfig';
+
+const MyClassesSkeleton = () => (
+  <div className="flex justify-center items-center h-64">
+    <CircularProgress />
+  </div>
+);
 
 const MyClassesPage: React.FC = () => {
   const { profile } = useUser();
+  const { selectedInstituteId } = useNeoInstitute();
   const {
     myClasses,
     classesLoading: myClassesLoading,
@@ -14,8 +24,16 @@ const MyClassesPage: React.FC = () => {
   } = useTimetableStore();
 
   useEffect(() => {
-    fetchMyClasses();
-  }, [fetchMyClasses]);
+    fetchMyClasses().catch((error) =>
+      logger.warn('my-classes', 'Fetch my classes failed', {
+        message: error instanceof Error ? error.message : String(error),
+      })
+    );
+  }, [fetchMyClasses, selectedInstituteId]);
+
+  if (myClassesLoading) {
+    return <MyClassesSkeleton />;
+  }
 
   const getRoleLabel = (role: string) => {
     switch (role) {
@@ -36,14 +54,6 @@ const MyClassesPage: React.FC = () => {
     }
   };
 
-  if (myClassesLoading) {
-    return (
-      <div className="flex justify-center items-center h-64">
-        <div className="animate-spin rounded-full h-12 w-12 border-b-2 border-blue-600"></div>
-      </div>
-    );
-  }
-
   if (myClassesError) {
     return (
       <div className="max-w-7xl mx-auto px-4 sm:px-6 lg:px-8 py-8">