Function gatherRecipientDocuments

gatherRecipientDocuments(
    participants: GroupParticipant[],
    owner: OwnerRecord,
    registry: Registry,
): XIDDocument[]
Gather XIDDocuments for all participants from the registry.

Port of gather_recipient_documents() from cmd/sign/coordinator/invite.rs lines 198-222.
Parameters
- participants: GroupParticipant[]
- owner: OwnerRecord
- registry: Registry
Returns XIDDocument[]
- Defined in cmd/sign/coordinator/invite.ts:100