Implement version 0.0.2 features

Add product version management:
- ProductVersion model and VersionManager class
- VersionAdminController with meta box on product edit page
- AJAX-based version CRUD (add, delete, toggle status)
- JavaScript for version management UI

Add email notifications:
- LicenseEmailController for order emails
- License keys included in order completed emails
- Support for both HTML and plain text emails

Add REST API rate limiting:
- 30 requests per minute per IP
- Cloudflare and proxy-aware IP detection
- HTTP 429 response with Retry-After header

Other changes:
- Bump version to 0.0.2
- Update CHANGELOG.md
- Add version status styles to admin.css

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

wc-licensed-product.php

@@ -3,7 +3,7 @@
  * Plugin Name: WooCommerce Licensed Product
  * Plugin URI: https://src.bundespruefstelle.ch/magdev/wc-licensed-product
  * Description: WooCommerce plugin to sell software products using license keys with domain-based validation.
- * Version: 0.0.1
+ * Version: 0.0.2
  * Author: Marco Graetsch
  * Author URI: https://src.bundespruefstelle.ch/magdev
  * License: GPL-2.0-or-later
@@ -28,7 +28,7 @@ if (!defined('ABSPATH')) {
 }
 
 // Plugin constants
-define('WC_LICENSED_PRODUCT_VERSION', '0.0.1');
+define('WC_LICENSED_PRODUCT_VERSION', '0.0.2');
 define('WC_LICENSED_PRODUCT_PLUGIN_FILE', __FILE__);
 define('WC_LICENSED_PRODUCT_PLUGIN_DIR', plugin_dir_path(__FILE__));
 define('WC_LICENSED_PRODUCT_PLUGIN_URL', plugin_dir_url(__FILE__));