Add RespondToControlCommandAsync to FakeWorkerHarness so scripted fake
workers can auto-reply to the five control command kinds (Ping,
GetSessionState, GetWorkerInfo, DrainEvents, ShutdownWorker) with canned
replies whose shapes match the real WorkerPipeSession helpers.
Add five unit tests in FakeWorkerHarnessTests covering each control
command kind through the WorkerClient→pipe roundtrip, and one gateway
E2E test (GatewayService_WithFakeWorker_ControlCommandsRoundtripThroughGateway)
that exercises Ping, GetWorkerInfo, and DrainEvents through the full
gRPC→SessionManager→WorkerClient→named-pipe path using a scripted
ControlCommandFakeWorkerProcessLauncher.
Joseph Doherty
bb5139fec2