FlowableWorkflowClient implements IRegistratieVerlopenClient (acquire/complete the
RegistratieVerlopen jobs) and CompleteDocumentWaitAsync (complete WachtOpDocumenten,
best-effort). Wires the RegistratieVerlopenProcessor + hosted RegistratieVerlopenPump
into the domain host and excludes the pump from mutation (like the other pumps).
Fakes updated for the new IWorkflowClient member.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>