Fix playback flush and speech interruption races

[toubatbrian]

Summary

Fixes several related playback/interruption races found while debugging the agents-js repro:

• Prevent ParticipantAudioOutput.flush() from canceling/replacing an active flush for the same playback segment, which could emit duplicate playback_finished events and desync segment counters.
• Make VAD/adaptive interruption end agent speech only once per paused speech handle, avoiding repeated onEndOfAgentSpeech() cascades.
• Ensure AudioRecognition leaves isAgentSpeaking before waiting on interruption sentinel delivery, so STT does not remain stuck buffering user speech.
• End audio-recognition speech when pipeline completion moves the session from speaking to listening.
• Handle confirmed interruption when only a paused speech remains, so later user speech is not treated as permanent overlap/interruption.
• Stop tool-reply continuation after tool execution if the speech handle was interrupted.

Verification

• Added regression coverage for duplicate flush finishing.
• Added regression coverage for repeated VAD interruption on the same paused speech.
• Added regression coverage for pipeline completion ending audio recognition.
• Added regression coverage for confirmed interruption with only paused speech.
• Added deterministic AudioRecognition regression for STT buffering while agent speech end is in progress.
• Verified repro logs before/after: max onEndOfAgentSpeech() burst dropped from 36 to 1, and STT no longer stays stuck buffering after interruption.

[changeset-bot]

🦋 Changeset detected

Latest commit: 42261c3

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 31 packages

Name	Type
@livekit/agents	Patch
@livekit/agents-plugin-anam	Patch
@livekit/agents-plugin-assemblyai	Patch
@livekit/agents-plugin-baseten	Patch
@livekit/agents-plugin-bey	Patch
@livekit/agents-plugin-cartesia	Patch
@livekit/agents-plugin-cerebras	Patch
@livekit/agents-plugin-deepgram	Patch
@livekit/agents-plugin-elevenlabs	Patch
@livekit/agents-plugin-fishaudio	Patch
@livekit/agents-plugin-google	Patch
@livekit/agents-plugin-hedra	Patch
@livekit/agents-plugin-hume	Patch
@livekit/agents-plugin-inworld	Patch
@livekit/agents-plugin-lemonslice	Patch
@livekit/agents-plugin-liveavatar	Patch
@livekit/agents-plugin-livekit	Patch
@livekit/agents-plugin-minimax	Patch
@livekit/agents-plugin-mistral	Patch
@livekit/agents-plugin-mistralai	Patch
@livekit/agents-plugin-neuphonic	Patch
@livekit/agents-plugin-openai	Patch
@livekit/agents-plugin-phonic	Patch
@livekit/agents-plugin-resemble	Patch
@livekit/agents-plugin-rime	Patch
@livekit/agents-plugin-runway	Patch
@livekit/agents-plugin-sarvam	Patch
@livekit/agents-plugin-silero	Patch
@livekit/agents-plugins-test	Patch
@livekit/agents-plugin-trugen	Patch
@livekit/agents-plugin-xai	Patch

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[devin-ai-integration]

✅ Devin Review: No Issues Found

Devin Review analyzed this PR and found no potential bugs to report.

View in Devin Review to see 5 additional findings.