NorskManager.notifyMigrationCutoverReady() method
Tell the source worker "the target is ready at payload; stop output at or after it". AutoManager calls this when it receives MigrationTargetReadyEvent from the target; payload is the target’s own, relayed opaque — the job owns its meaning.
Signature:
notifyMigrationCutoverReady(sourceJobKey: ActiveJobKey, migrationId: string, payload: Uint8Array): Promise<void>;