fix: alert topic id not being set after getting started controller

src/User/Framework/Controller/Web/RegistrationController.php

@@ -17,13 +17,16 @@ use Psr\Log\LoggerInterface;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Bundle\SecurityBundle\Security;
 use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\RequestStack;
 use Symfony\Component\HttpFoundation\Response;
 use Symfony\Component\HttpKernel\KernelInterface;
 use Symfony\Component\Routing\Attribute\Route;
 
 class RegistrationController extends AbstractController
 {
-    public function __construct(private readonly RegisterUserHandler $registerUserHandler)
+    public function __construct(private readonly RegisterUserHandler $registerUserHandler,
+        private readonly RequestStack $requestStack
+    )
     {
     }
 
@@ -71,6 +74,7 @@ class RegistrationController extends AbstractController
             ));
 
             $security->login($user->user);
+            $this->requestStack->getCurrentRequest()->getSession()->set('mercure_alert_topic', 'alerts_' . uniqid());
 
             return $this->redirectToRoute('app_index');
         }