wip: modernized edit flow

src/Form/Model/BookingDtoInterface.php

@@ -14,6 +14,16 @@ namespace App\Form\Model;
  */
 interface BookingDtoInterface
 {
+    public const MODE_CREATE = 'create';
+    public const MODE_EDIT = 'edit';
+
+    /**
+     * Gets the booking mode (create or edit).
+     *
+     * @return string One of MODE_CREATE or MODE_EDIT constants
+     */
+    public function getMode(): string;
+
     /**
      * Gets all participants in the booking.
      *