6b1cb9e0e6
- Remove redundant linked CancellationTokenSource in ProbeAsync; pass the framework cancellationToken and ProbeTimeout directly to Ask (the two-CTS pattern was redundant — Ask already honours both the timeout and the token). - Add EchoActor XML <remarks> explaining why no Receive<Identify> handler is needed (ActorBase answers Identify automatically). - Add PreCancelledToken_ReportsUnhealthy_DoesNotThrow test: verifies the never-throws guarantee on the shutdown-race path (token already cancelled before CheckHealthAsync is invoked).