feat(elevenlabs): support previous text for realtime STT

[rosetta-livekit-bot]

Summary

• Add previousText to ElevenLabs STT options, keeping it for scribe_v2_realtime and warning/ignoring it for non-realtime models.
• Send previous_text once as the first realtime input_audio_chunk on websocket connections.
• Add adapted source parity tests and a changeset for @livekit/agents-plugin-elevenlabs.

Source diff coverage

Coverage classification

• livekit-plugins/livekit-plugins-elevenlabs/livekit/plugins/elevenlabs/stt.py: ported to plugins/elevenlabs/src/stt.ts. Python previous_text maps to JS previousText; constructor warning/ignore behavior maps directly; realtime websocket sends an initial empty input_audio_chunk with previous_text before any audio/keepalive task.
• tests/test_plugin_elevenlabs_stt.py: adapted to plugins/elevenlabs/src/stt.test.ts. JS private fields prevent direct _opts assertions, so the realtime retention assertion is adapted to observe the first websocket message; the non-realtime ignore/warning assertion is ported by spying on the package logger.

Testing

• pnpm test plugins/elevenlabs/src/stt.test.ts
• pnpm --filter @livekit/agents-plugin-elevenlabs build
• pnpm --filter @livekit/agents-plugin-elevenlabs lint
• pnpm test plugins/elevenlabs
• pnpm build
• pnpm lint (passes with existing warnings)
• pnpm --filter @livekit/agents-plugin-elevenlabs api:check (fails because this package has no checked-in API report, with existing missing release-tag warnings)

---

Ported from livekit/agents#6534

Original PR description

Summary

• Add previous_text to ElevenLabs realtime STT (scribe_v2_realtime)
• After each WebSocket connect (including reconnect), send it on a priming empty input_audio_chunk so it is always the first chunk on the connection (ElevenLabs requires this)

Fixes #6074

Test plan

• uv run pytest tests/test_plugin_elevenlabs_stt.py --plugin elevenlabs

[changeset-bot]

🦋 Changeset detected

Latest commit: e9ce1fa

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-plugin-elevenlabs	Major
@livekit/agents	Major
@livekit/agents-plugin-anam	Major
@livekit/agents-plugin-anthropic	Major
@livekit/agents-plugin-assemblyai	Major
@livekit/agents-plugin-azure	Major
@livekit/agents-plugin-baseten	Major
@livekit/agents-plugin-bey	Major
@livekit/agents-plugin-cartesia	Major
@livekit/agents-plugin-cerebras	Major
@livekit/agents-plugin-deepgram	Major
@livekit/agents-plugin-did	Major
@livekit/agents-plugin-fishaudio	Major
@livekit/agents-plugin-google	Major
@livekit/agents-plugin-hedra	Major
@livekit/agents-plugin-hume	Major
@livekit/agents-plugin-inworld	Major
@livekit/agents-plugin-krisp	Major
@livekit/agents-plugin-lemonslice	Major
@livekit/agents-plugin-liveavatar	Major
@livekit/agents-plugin-livekit	Major
@livekit/agents-plugin-minimax	Major
@livekit/agents-plugin-mistral	Major
@livekit/agents-plugin-mistralai	Major
@livekit/agents-plugin-neuphonic	Major
@livekit/agents-plugin-openai	Major
@livekit/agents-plugin-perplexity	Major
@livekit/agents-plugin-phonic	Major
@livekit/agents-plugin-protoface	Major
@livekit/agents-plugin-resemble	Major
@livekit/agents-plugin-rime	Major
@livekit/agents-plugin-runway	Major
@livekit/agents-plugin-sarvam	Major
@livekit/agents-plugin-silero	Major
@livekit/agents-plugin-soniox	Major
@livekit/agents-plugin-tavus	Major
@livekit/agents-plugin-trugen	Major
@livekit/agents-plugin-xai	Major
@livekit/agents-plugins-test	Major

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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.