feat: add full-screen exam delivery UI with JWT auth fix

- Fix jwt_required decorator to set request.env user context via
  update_env() instead of passing user as kwarg (fixes null student_id
  on attempt creation for auth='none' API routes)
- Build standalone exam session page with timer, question navigator,
  auto-save, and instant score display (no dependency on web.frontend_layout)
- Add exam_delivery.js for client-side exam interaction (MCQ selection,
  section navigation, countdown, autosave, submit & results)
- Generate per-session JWT in controller for API calls from the exam page

Made-with: Cursor

new_project/custom_addons/encoach_api/controllers/base.py

@@ -70,13 +70,14 @@ def validate_token():
 
 
 def jwt_required(func):
-    """Decorator that validates the JWT token and injects the user as first arg."""
+    """Decorator that validates the JWT token and sets request.env user context."""
     @functools.wraps(func)
     def wrapper(*args, **kwargs):
         user = validate_token()
         if not user:
             return _error_response("Authentication required", status=401)
-        return func(*args, user=user, **kwargs)
+        request.update_env(user=user.id)
+        return func(*args, **kwargs)
     return wrapper