Use MicroKernelTrait to bootstrap application. Rewrote routes, controllers and structure of application a bit. Including use of twig.

src/Controller/StarController.php

@@ -3,12 +3,16 @@
 namespace Krzysiej\RyobiCrawler\Controller;
 
 use Krzysiej\RyobiCrawler\Models\Product;
+use Symfony\Component\HttpFoundation\Request;
+use Symfony\Component\HttpFoundation\Response;
+use Symfony\Component\Routing\Attribute\Route;
 
 final class StarController extends BaseController
 {
-    public function __invoke(int $productId): void
+    #[Route('/star/{productId<\d+>}', name: 'app_star')]
+    public function __invoke(int $productId, Request $request): Response
     {
         Product::find($productId)->toggleStarred()->save();
-        header('Location: ' . $_SERVER['HTTP_REFERER']);
+        return $this->redirect($request->headers->get('referer'));
     }
 }