feat: update product and variant resources to improve variant selection handling and response structure

app/Domains/Catalog/Controllers/ProductController.php

@@ -59,7 +59,7 @@ class ProductController extends Controller
     protected function resolveScopedProduct(Tenant $tenant, Product $product): Product
     {
         if ($product->tenant_codigo !== $tenant->codigo) {
-            throw new NotFoundHttpException('Product not found for tenant.');
+            throw new NotFoundHttpException('Product not found.');
         }
 
         return $product;