finalizeSessionIfUnresolved(sessionId: string,attendeeId: number,paymentReference: TaggedPaymentReference | null,): Promise<void>
Heals a reservation ONLY while it is unresolved, so it never overwrites the
attendee_id or blanks the ticket_tokens a racing delivery just finalized.
The guard is UNRESOLVED_RESERVATION, so the first outcome wins.
A replayed paymentReference is stored too. After a prune, that is the only
refundable id a provider-less or admin-added attendee's balance charge has.