83e9ffd27a
Review R1 M2: since #597 the SDK timer fires at real expiry, and OnTimedUnshelve routed an operator-style Unshelve by 'system' from both pair nodes, pre-empting the engine's AutoUnshelve. The engine owns expiry, so the callback now routes nothing. Integration test: an engine stand-in that acts on a routed Unshelve and expires late, plus a wrapped OnTimedUnshelve (positive control: the SDK timer fired). Review R1 m1: Part9StateMachine.ApplyAcknowledge records a commented re-ack as AddComment (persisted and replicated) instead of a NoOp; an uncommented re-ack is still a no-op. Claude-Session: https://claude.ai/code/session_01Ef2ozxS7QPanGT8uoATbTe