feat: initialize React admin build pipeline (F2.1-F2.6)

- Add package.json with @wordpress/scripts and React dependencies
- Configure webpack for admin bundle output
- Create src/admin directory structure (api, components, pages)
- Implement API client with nonce handling (ajaxRequest, apiRequest)
- Add API methods for orders, customers, products, forms, coupons, licenses
- Create React App component with page routing
- Add placeholder page components for all admin sections
- Create ReactAdmin PHP class to manage asset enqueuing
- Register ReactAdmin singleton in main plugin file
- Bump version to 2.0.0

Build: Run 'npm install && npm run build' to generate assets

formipay.php

@@ -2,7 +2,7 @@
 /**
  * Plugin Name:       Formipay
  * Description:       -
- * Version:           1.0.0
+ * Version:           2.0.0
  * Plugin URI:        https://formipay.com/
  * Author:            Formipay
  * Text Domain:       formipay
@@ -21,7 +21,7 @@
 if ( ! defined( 'ABSPATH' ) ) exit;
 
 define( 'FORMIPAY_NAME', 'Formipay' );
-define( 'FORMIPAY_VERSION', '1.0.0' );
+define( 'FORMIPAY_VERSION', '2.0.0' );
 define( 'FORMIPAY_PATH', plugin_dir_path( __FILE__ ) );
 define( 'FORMIPAY_URL', plugin_dir_url( __FILE__ ) );
 define( 'FORMIPAY_MENU_SLUG', 'formipay' );
@@ -49,6 +49,7 @@ spl_autoload_register(function ($class) {
 });
 
 \Formipay\Init::get_instance();
+\Formipay\Admin\ReactAdmin::get_instance();
 
 register_activation_hook( __FILE__, 'formipay_activate' );
 function formipay_activate() {