Complete Multi-card Pre-authorization

Send POST /payment/v1/card-payments/{conversationId}/multi_post-auth with the merchantId header. The path value conversationId must be the same value used for all related pre-authorization requests.

The JSON body uses paidPrice, a positive amount with an API maximum of 2,000,000. For this multi-card operation, the service uses only paidPrice from the shared post-authorization request model; it must represent the total amount to close.

The response contains conversationId, paymentMultiCardStatus, multiPayment (always true for this response), and paymentIdList containing the related payment identifiers.