Implement localization for API responses and error messages

- Added localization support for API responses in English and Spanish.
- Introduced a middleware to set the API locale based on the Accept-Language header.
- Updated various exception messages and validation responses to use localized strings.
- Created new language files for English and Spanish translations.
- Refactored existing code to replace hardcoded messages with localized strings.
- Added tests to verify localization functionality and response correctness.

app/Domains/Cart/Controllers/CartController.php

@@ -36,7 +36,10 @@ class CartController extends Controller
         );
 
         $response = CartResource::make($result['cart'])
-            ->additional(['message' => 'Producto agregado al carrito.'])
+            ->additional([
+                'code' => 'cart.item_added',
+                'message' => __('api.cart.item_added'),
+            ])
             ->response();
 
         if ($result['guest_token'] !== null) {
@@ -58,13 +61,19 @@ class CartController extends Controller
                 $cartItem->getKey(),
                 (int) $request->validated('cantidad'),
             )
-        )->additional(['message' => 'Cantidad de producto actualizada.']);
+        )->additional([
+            'code' => 'cart.quantity_updated',
+            'message' => __('api.cart.quantity_updated'),
+        ]);
     }
 
     public function removeItem(Request $request, Tenant $tenant, CartItem $cartItem): CartResource
     {
         return CartResource::make(
             $this->cartService->removeItem($tenant, $request, $cartItem->getKey())
-        )->additional(['message' => 'Producto eliminado del carrito.']);
+        )->additional([
+            'code' => 'cart.item_removed',
+            'message' => __('api.cart.item_removed'),
+        ]);
     }
 }