Why: A domain outbox could not correlate its committed event with the host receipt because the bus generated the operation ID after the handler returned.
Evidence: RED-to-GREEN bus and compiled-handler tests; local go test ./... -count=1 and isolated PostgreSQL operation/link checks passed as SELF.
Impact: Expose a host-generated operation ID to handlers and resolve a unique committed audit offset after dispatch; missing receipts remain retryable and ambiguous rows fail closed.
Refs: Stage 5 W9; approved Stage 6 audit-link design adjustment r1