3a3d9e8e06
TryStartCommandTask returned silently when command intake had stopped, so a command refused during shutdown got no reply and no log and the gateway's correlation wait ran out its own timeout. The refusal now writes a WorkerUnavailable reply for the correlation and logs WorkerCommandRejectedAfterShutdown. StopAcceptingCommands is internal so the test can reach the guard (the serial read loop cannot race it today). Test: WorkerPipeSessionTests.CommandAfterShutdown_RepliesWorkerUnavailable.