Returns transfers that have settled, newest first. Each record is the
registry's proof that a position moved between two parties, and settlement is
final — a settled transfer is never reversed. A correction appears as a
separate compensating transfer rather than as a change to this record.

Where instructionContractId is present it links the transfer back to the
instruction that authorised it. The field is optional, so reconcile settlement
against instruction flow by matching sender, receiver, instrument and amount, and
treat the explicit link as an optimisation rather than the mechanism.