Expire replay instructions in the live appended context

Continuous appended conversation history retains old recovery directives after native state has resolved them. For an owed introduction in Pipecat, clearing a flag after playback still leaves an earlier model instruction to replay it. Append a completion receipt to the actual model context at the correlated playback-completion hook. Test that live history rather than rebuilding the next node to simulate completion: the current step may remain active until another caller turn. Require positive audio from the replay's own TTS context and reject interrupted or stale-turn completion before expiring the directive. Framework completion signals do not establish handset audibility.

Applies when: Appended model context contains a recovery instruction tied to speech completion. Keywords: Pipecat APPEND context introduction replay TTS receipt interruption completion