feat: improved promotional and purchase vouchers

src/Form/Model/ParticipantDto.php

@@ -127,6 +127,15 @@ class ParticipantDto
     )]
     public ?string $purchaseVoucherCode = null;
 
+    /**
+     * Flag indicating if the purchase voucher is a goodwill (Kulanz) voucher.
+     *
+     * Goodwill vouchers are treated as promotional vouchers in BPN XML
+     * (sent as <aktionscode> per participant, not in <gutscheine> collection).
+     * Set by ParticipantPurchaseVoucherFieldHandler during form processing.
+     */
+    public bool $hasGoodwillVoucher = false;
+
     /**
      * Promo voucher code.
      * Applied per participant in booking payload as <aktionscode>.