fix(room_io): don't re-fire playbackStarted on resume

[rosetta-livekit-bot]

Ports livekit/agents#6636.

Summary

• preserve the per-segment playbackStarted latch across mid-segment pause/resume
• add the matching pause/resume regression test
• add a patch changeset for @livekit/agents

Validation

• pnpm test agents (111 files passed, 1510 tests passed, 5 skipped)
• pnpm build
• pnpm lint
• cue-cli voice-mode runtime assertion: agent entered AS_SPEAKING and committed an ASSISTANT conversation item

Source diff coverage

Source file	Classification	Target coverage
livekit-agents/livekit/agents/voice/room_io/_output.py	Adapted	agents/src/voice/room_io/_output.ts: preserve the JS firstFrameEmitted latch across resume(); it corresponds to the Python _first_frame_event and remains reset at segment completion.
tests/test_room_io.py	Adapted	agents/src/voice/room_io/_output.test.ts: port the source regression scenario into the target co-located output suite, asserting one playbackStarted before and after a mid-segment pause/resume.

No source files were omitted and no supporting infrastructure gap exists in the target. The changeset is target-only release metadata.

---

Ported from livekit/agents#6636

Original PR description

fix _SegmentSynchronizerImpl.on_playback_started called after start_fut is set warning after resumed false interrupted speech

[changeset-bot]

🦋 Changeset detected

Latest commit: 1d80485

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

This PR includes changesets to release 39 packages

Name	Type
@livekit/agents	Patch
@livekit/agents-plugin-anam	Patch
@livekit/agents-plugin-anthropic	Patch
@livekit/agents-plugin-assemblyai	Patch
@livekit/agents-plugin-azure	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-did	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-krisp	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-perplexity	Patch
@livekit/agents-plugin-phonic	Patch
@livekit/agents-plugin-protoface	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-plugin-soniox	Patch
@livekit/agents-plugin-tavus	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 1 additional finding.