Add guest management and GDPR privacy compliance (v0.4.0)

- Create Guest CPT with personal info, address, ID/passport tracking
- Add guest-booking integration with AJAX search and linking
- Implement GDPR compliance via WordPress Privacy API (export/erasure)
- Update EmailNotifier to use Guest CPT data with new placeholders
- Add CSS styles for guest search, linked display, and privacy UI

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: 0.3.0
+ * Version: 0.4.0
  * 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', '0.3.0' );
+define( 'WP_BNB_VERSION', '0.4.0' );
 
 // Plugin path constants.
 define( 'WP_BNB_PATH', plugin_dir_path( __FILE__ ) );
@@ -165,6 +165,8 @@ function wp_bnb_activate(): void {
 		\Magdev\WpBnb\Taxonomies\RoomType::register();
 		\Magdev\WpBnb\PostTypes\Building::register();
 		\Magdev\WpBnb\PostTypes\Room::register();
+		\Magdev\WpBnb\PostTypes\Booking::register();
+		\Magdev\WpBnb\PostTypes\Guest::register();
 	}
 
 	// Set default options.