feat(#159): suppressions métier dossiers/parents/enfants/AM/staff.

SuppressionService + DELETE /dossiers/:numero, cascades DELETE /users et
DELETE /enfants?deleteDossier, flag sans_enfant, specs front #160.

Co-authored-by: Cursor <cursoragent@cursor.com>

backend/src/routes/user/user.service.ts

@@ -520,6 +520,7 @@ export class UserService {
     }
 
     async remove(id: string, currentUser: Users): Promise<void> {
+        // Délégué historiquement ; préférer SuppressionService via controller (#159).
         if (currentUser.role !== RoleType.SUPER_ADMIN) {
             throw new ForbiddenException('Accès réservé aux super admins');
         }