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

woonoow.php

@@ -40,6 +40,7 @@ add_action('plugins_loaded', function () {
     // Initialize module settings
     WooNooW\Modules\NewsletterSettings::init();
     WooNooW\Modules\WishlistSettings::init();
+    WooNooW\Modules\Licensing\LicensingModule::init();
 });
 
 // Activation/Deactivation hooks