feat: refactor cart item handling to use mapped buyable types and improve method signatures

app/Domains/Cart/Requests/AddCartItemRequest.php

@@ -22,4 +22,13 @@ class AddCartItemRequest extends FormRequest
             'cantidad' => ['required', 'integer', 'min:1'],
         ];
     }
+
+    public function mappedBuyableType(): string
+    {
+        return match ($this->input('buyable_type')) {
+            'variant' => \App\Domains\Catalog\Models\ProductVariant::class,
+            'bundle' => \App\Domains\Bundle\Models\Bundle::class,
+            default => throw new \InvalidArgumentException('Invalid buyable type'),
+        };
+    }
 }