feat(phase-b): student enrollment UI, teacher/student management pages, lesson views

- ClassDetailPage: full rewrite with MUI tabs (students, enrollment requests, teachers),
  add/remove students, approve/reject enrollment requests, AddStudentDialog
- StudentLessonsPage: new — student's weekly lesson view with week navigation
- TaughtLessonsPage: teacher's taught lesson week view
- SchoolSettingsPage, StaffManagerPage, StudentManagerPage: school admin management pages
- PlatformAdminPage: platform admin reset/seed controls
- Header: expanded nav menu (student lessons, school management, platform admin items)
- AppRoutes: routes for all new pages
- SchoolCalendarWizard, TeacherTimetableWizard: week_cycle support and improvements
- CCGraphNavPanel: updated navigation integration
- index.ts: export all new timetable pages

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

src/utils/tldraw/ui-overrides/components/shared/navigation/CCGraphNavPanel.tsx

@@ -170,8 +170,12 @@ function TreeItem({ node, depth, onSelect, onExpand }: TreeItemProps) {
     const handleClick = () => {
         if (!isSection) {
             onSelect(node);
-        } else if (canExpand || (isCalendarSection && ctx.calendarMode === 'academic')) {
-            handleToggle({ stopPropagation: () => {} } as React.MouseEvent);
+        } else {
+            // Sections with a real node ID (e.g. the school section) navigate AND expand
+            if (node.neo4j_node_id) onSelect(node);
+            if (canExpand || (isCalendarSection && ctx.calendarMode === 'academic')) {
+                handleToggle({ stopPropagation: () => {} } as React.MouseEvent);
+            }
         }
     };
 
@@ -516,7 +520,7 @@ export function CCGraphNavPanel() {
     }, [accessToken, apiBase]);
 
     const handleSelect = useCallback((node: TreeNode) => {
-        if (!node.is_section) navigateToNeoNode(node);
+        if (!node.is_section || node.neo4j_node_id) navigateToNeoNode(node);
     }, [navigateToNeoNode]);
 
     const refreshAll = useCallback(() => {