feat: stages module, mobility frontend, theme toggle, employeeOnly access control

- Add stages module with full CRUD API and admin overview island
- Add mobility overview island (Liste, Kanban, Detail CRUD views)
- Add contract PDF upload/download endpoints for mobilites
- Add light/dark theme toggle in header
- Add employeeOnly flag to hide entire modules from students (admin, students, stages)
- Add read-only GET endpoints for modules/ues/ue-modules in notes module
- Add [slug].tsx catch-all routes for direct URL navigation
- Replace old mobility table with mobilites + stages schema (migration 0004)
- Allow students to create mobilites and upload contracts
- Redirect authenticated users from / to /apps catalog

routes/(apps)/notes/(_islands)/NotesView.tsx

@@ -62,9 +62,9 @@ export default function NotesView({ numEtud, prenom }: Props) {
       try {
         const [notesRes, uesRes, ueModRes, modRes, ajRes] = await Promise.all([
           fetch(`/notes/api/notes?numEtud=${numEtud}`),
-          fetch("/admin/api/ues"),
-          fetch("/admin/api/ue-modules"),
-          fetch("/admin/api/modules"),
+          fetch("/notes/api/ues"),
+          fetch("/notes/api/ue-modules"),
+          fetch("/notes/api/modules"),
           fetch(`/notes/api/ajustements?numEtud=${numEtud}`),
         ]);