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)/students/api/students/[numEtud].ts

@@ -2,8 +2,9 @@ import { FreshContext, Handlers } from "$fresh/server.ts";
 import { db } from "$root/databases/db.ts";
 import {
   ajustements,
-  mobility,
+  mobilites,
   notes,
+  stages,
   students,
 } from "$root/databases/schema.ts";
 import { AuthenticatedState } from "$root/defaults/interfaces.ts";
@@ -80,7 +81,7 @@ export const handler: Handlers<null, AuthenticatedState> = {
   },
 
   // #12 DELETE /students/{numEtud}
-  // Cascade: deletes notes, ajustements, mobility for this student.
+  // Cascade: deletes notes, ajustements, mobilites, stages for this student.
   async DELETE(
     _request: Request,
     context: FreshContext<AuthenticatedState>,
@@ -102,7 +103,8 @@ export const handler: Handlers<null, AuthenticatedState> = {
     await db.transaction(async (tx) => {
       await tx.delete(notes).where(eq(notes.numEtud, numEtud));
       await tx.delete(ajustements).where(eq(ajustements.numEtud, numEtud));
-      await tx.delete(mobility).where(eq(mobility.studentId, numEtud));
+      await tx.delete(mobilites).where(eq(mobilites.numEtud, numEtud));
+      await tx.delete(stages).where(eq(stages.numEtud, numEtud));
       await tx.delete(students).where(eq(students.numEtud, numEtud));
     });