Refactor project structure to use domain-oriented architecture; add Product and Tenant domains with controllers, models, requests, resources, and routes

app/Domains/Product/Services/ProductService.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace App\Domains\Product\Services;
+
+class ProductService
+{
+    // Reserved for product domain business logic.
+}