fix(elevenlabs): enforce TTS WebSocket context limit

[swayamg20]

Description

Fixes #1985.

Rapid interruptions could enqueue a replacement ElevenLabs TTS context before the provider finalized an interrupted one. Because ElevenLabs allows up to five concurrent contexts, a sixth context could trigger max_active_conversations and reset the shared socket.

Changes Made

• Track active and closing contexts and defer new-context admission until ElevenLabs finalizes a previous context.
• Prioritize cancellation cleanup, remove queued content for interrupted streams, and prevent text from being sent after close_context.
• Preserve per-context ordering and graceful flush-before-close behavior.
• Add regression coverage for rapid interruptions at the five-context limit, cancellation before startup, and graceful stream closure.
• Add a patch changeset for @livekit/agents-plugin-elevenlabs.

Pre-Review Checklist

• Build passes: Build, lint, typecheck, formatting, throws, and scoped API checks pass locally on Node 24.
• AI-generated code reviewed: Removed unnecessary comments and reviewed the changes for correctness and code quality.
• Changes explained: Changes and their purpose are documented above.
• Scope appropriate: The three changed files are limited to the ElevenLabs fix, tests, and changeset.
• Video demo: Not applicable; this is WebSocket lifecycle logic covered by deterministic local-server tests.

Testing

• Automated tests added and updated.
• pnpm test plugins/elevenlabs/src/tts.test.ts --silent — 10 passed, 1 credential-gated test skipped on Node 24.
• pnpm build
• pnpm lint
• pnpm typecheck
• pnpm throws:check
• pnpm format:check
• pnpm --filter @livekit/agents-plugin-elevenlabs api:check
• restaurant_agent.ts and realtime_agent.ts are not applicable to this internal provider scheduling fix.

Additional Notes

The full monorepo suite was also exercised: 186 test files passed. The remaining failures were unrelated environment-dependent credential, network, and LFS cases plus an existing FishAudio test; the focused ElevenLabs suite passes.

[changeset-bot]

🦋 Changeset detected

Latest commit: dc921fd

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	Patch
@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-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-plugin-trugen	Patch
@livekit/agents-plugin-xai	Patch
@livekit/agents-plugins-test	Patch

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[devin-ai-integration]

✅ Devin Review: No Issues Found

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