Run an api fan-out. Returns a success envelope when the orchestration
completes (even if every target failed); throws only for pre-flight failures
(invalid method, CDB decrypt, unconfirmed write) the caller renders as an
outer error via buildApiFanoutErrorEnvelope.
Run an
apifan-out. Returns a success envelope when the orchestration completes (even if every target failed); throws only for pre-flight failures (invalid method, CDB decrypt, unconfirmed write) the caller renders as an outer error via buildApiFanoutErrorEnvelope.