feat: migrate app state to bootstrap endpoint

Use GET /me/bootstrap as the primary authenticated state source per ADR-0003. AuthContext now fetches and exposes typed bootstrapData, Header and class/detail admin checks use bootstrap permissions/roles, dashboard surfaces onboarding/calendar/timetable/graph status, and graph navigation derives school setup state from bootstrap instead of /school/status.

Refs: t_44353587

src/pages/timetable/ClassDetailPage.tsx

@@ -116,7 +116,7 @@ function AddStudentDialog({ open, onClose, onAdd, accessToken, existingIds }: Ad
 const ClassDetailPage: React.FC = () => {
     const { classId } = useParams<{ classId: string }>();
     const navigate = useNavigate();
-    const { accessToken, user } = useAuth();
+    const { accessToken, user, bootstrapData } = useAuth();
 
     const [cls, setCls] = useState<ClassDetail | null>(null);
     const [loading, setLoading] = useState(true);
@@ -131,24 +131,19 @@ const ClassDetailPage: React.FC = () => {
         setLoading(true);
         setError(null);
         try {
-            const [clsRes, roleRes] = await Promise.all([
-                fetch(`${API_BASE}/classes/${classId}`, {
-                    headers: { Authorization: `Bearer ${accessToken}` },
-                }).then(r => r.json()),
-                fetch(`${API_BASE}/school/status`, {
-                    headers: { Authorization: `Bearer ${accessToken}` },
-                }).then(r => r.json()),
-            ]);
+            const clsRes = await fetch(`${API_BASE}/classes/${classId}`, {
+                headers: { Authorization: `Bearer ${accessToken}` },
+            }).then(r => r.json());
             if (clsRes.id) setCls(clsRes);
             else setError(clsRes.detail || 'Class not found');
-            const role = roleRes.user_role || '';
+            const role = bootstrapData?.active_institute?.membership_role || '';
             setIsAdmin(role === 'school_admin' || role === 'department_head');
         } catch (e: any) {
             setError(e.message);
         } finally {
             setLoading(false);
         }
-    }, [accessToken, classId]);
+    }, [accessToken, classId, bootstrapData]);
 
     useEffect(() => { load(); }, [load]);