chore: fix phpstan errors

src/Controller/Booking/Create/Step2Controller.php

@@ -132,6 +132,7 @@ class Step2Controller extends AbstractController
         }
     }
 
+    /** @param array<int, \App\Form\Model\RoomSelectionDto> $roomSelections */
     private function calculateParticipantsCount(array $roomSelections, Travel $travelData): int
     {
         $participantsCount = 0;

src/Controller/Booking/Create/Step2ParticipantController.php

@@ -124,6 +124,7 @@ class Step2ParticipantController extends AbstractController
         );
     }
 
+    /** @param FormInterface<mixed> $form */
     private function renderParticipantForm(
         FormInterface $form,
         int $index,
@@ -157,6 +158,7 @@ class Step2ParticipantController extends AbstractController
         return $bookingDto;
     }
 
+    /** @return FormInterface<mixed> */
     private function createParticipantForm(BookingDto $bookingDto, int $index): FormInterface
     {
         $wrapper = $this->participantFormSupportService->createParticipantEditDto($bookingDto, $index);

src/Controller/Booking/Create/Step3Controller.php

@@ -220,6 +220,7 @@ class Step3Controller extends AbstractController
     /**
      * Renders the step 3 form with standard template variables.
      */
+    /** @param FormInterface<mixed> $form */
     private function renderStepForm(BookingDto $bookingCreateDto, FormInterface $form): Response
     {
         $context = $this->createContextFactory->create(

src/Controller/Booking/Create/Step4Controller.php

@@ -177,6 +177,9 @@ class Step4Controller extends AbstractController
     /**
      * Renders the step 4 form with standard template variables.
      */
+    /**
+     * @param FormInterface<mixed> $form
+     */
     private function renderStepForm(
         BookingDto $bookingCreateDto,
         FormInterface $form,

src/Controller/Booking/Create/SuccessController.php

@@ -8,6 +8,7 @@ use App\Service\BookingSessionManager;
 use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
 use Symfony\Component\HttpFoundation\Request;
 use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\HttpFoundation\Session\FlashBagAwareSessionInterface;
 use Symfony\Component\Routing\Attribute\Route;
 
 /**
@@ -23,11 +24,17 @@ class SuccessController extends AbstractController
     #[Route('/bookings/create/success', name: 'app_booking_create_success')]
     public function success(Request $request): Response
     {
-        $flashBag = $request->getSession()->getFlashBag();
+        $returnUrl = $this->bookingSessionService->getReturnUrl($request);
+        $session = $request->getSession();
+
+        if (!$session instanceof FlashBagAwareSessionInterface) {
+            return $this->redirect($returnUrl);
+        }
+
+        $flashBag = $session->getFlashBag();
         $bookingNumber = $flashBag->get('booking_number')[0] ?? null;
         $bookingTotal = $flashBag->get('booking_total')[0] ?? null;
         $travelName = $flashBag->get('booking_travel_name')[0] ?? null;
-        $returnUrl = $this->bookingSessionService->getReturnUrl($request);
 
         // Redirect to return URL if no booking number (direct access or refresh)
         if (null === $bookingNumber) {