Error envelope for a single fanout target. Unlike
buildRetrieveErrorEnvelope (which only knows the raw request and so
loses recordIndex / baseUrl / name / per-field sources), this preserves
the resolved per-target identity, auth, settings, and operation meta so a
failed inner envelope carries the same provenance as a successful one.
Error envelope for a single fanout target. Unlike buildRetrieveErrorEnvelope (which only knows the raw request and so loses
recordIndex/baseUrl/name/ per-field sources), this preserves the resolved per-target identity, auth, settings, and operation meta so a failed inner envelope carries the same provenance as a successful one.