Add additional services system (v0.5.0)

- Service CPT with pricing types: Included, Per Booking, Per Night
- ServiceCategory taxonomy with default categories
- Booking-services integration with service selector
- Real-time price calculation based on nights and quantity
- Services total and grand total display in booking admin

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

wp-bnb.php

@@ -3,7 +3,7 @@
  * Plugin Name: WP BnB Management
  * Plugin URI: https://src.bundespruefstelle.ch/magdev/wp-bnb
  * Description: A comprehensive Bed & Breakfast management system for WordPress. Manage buildings, rooms, bookings, and guests.
- * Version: 0.4.0
+ * Version: 0.5.0
  * Requires at least: 6.0
  * Requires PHP: 8.3
  * Author: Marco Graetsch
@@ -24,7 +24,7 @@ if ( ! defined( 'ABSPATH' ) ) {
 }
 
 // Plugin version constant - MUST match Version in header above.
-define( 'WP_BNB_VERSION', '0.4.0' );
+define( 'WP_BNB_VERSION', '0.5.0' );
 
 // Plugin path constants.
 define( 'WP_BNB_PATH', plugin_dir_path( __FILE__ ) );