feat: Add licensing module backend

- LicensingSettings.php with key format, activation limits, expiry settings
- LicenseManager.php with key generation, activation/deactivation, validation
- LicensingModule.php with WooCommerce product meta integration
- LicensesController.php with admin, customer, and public API endpoints
- Database tables: woonoow_licenses, woonoow_license_activations
- has_settings enabled in ModuleRegistry

includes/Api/Routes.php

@@ -25,6 +25,7 @@ use WooNooW\Api\ModulesController;
 use WooNooW\Api\ModuleSettingsController;
 use WooNooW\Api\CampaignsController;
 use WooNooW\Api\DocsController;
+use WooNooW\Api\LicensesController;
 use WooNooW\Frontend\ShopController;
 use WooNooW\Frontend\CartController as FrontendCartController;
 use WooNooW\Frontend\AccountController;
@@ -158,6 +159,9 @@ class Routes {
             // Campaigns controller
             CampaignsController::register_routes();
             
+            // Licenses controller (licensing module)
+            LicensesController::register_routes();
+            
             // Modules controller
             $modules_controller = new ModulesController();
             $modules_controller->register_routes();