feat(xai): add TTS websocket pooling

[rosetta-livekit-bot]

Summary

Add xAI TTS support to the JS plugin and configure its pooled websocket lifetime below xAI's undocumented server-side deadline.

The source change only adjusted the xAI TTS websocket pool deadline, but the target repo did not yet have an xAI TTS implementation. This PR ports the missing TTS infrastructure so the deadline behavior exists in agents-js rather than dropping it.

Source diff coverage

• livekit-plugins/livekit-plugins-xai/livekit/plugins/xai/tts.py: adapted to plugins/xai/src/tts.ts and plugins/xai/src/index.ts. The target had no xAI TTS counterpart, so this ports the missing xAI websocket TTS implementation into the xAI plugin, exports it publicly, and applies the source change as maxSessionDuration: 1_800_000 ms, the JS equivalent of Python's 1800 seconds. The source comment about xAI's undocumented roughly 2100s websocket deadline is preserved next to the pool setting.

Testing

• pnpm test plugins/xai (8 passed, 1 skipped)
• pnpm --filter @livekit/agents-plugin-xai build
• pnpm --filter @livekit/agents-plugin-xai lint
• pnpm build
• Added focused websocket tests covering fresh connection reuse, rotation after 1,800,000 ms, multi-segment streaming, and provider capabilities.

The package lint completes with two pre-existing no-explicit-any warnings in plugins/xai/src/_utils.ts.

Runtime validation

• Live xAI synthesis with the capitalized Python-parity voice Ara returned 24 kHz mono PCM successfully.
• Two sequential chunked syntheses plus two flushed streaming segments reused one live xAI websocket.
• Cue voice-mode session sid_07063c0f2886 exercised the changed provider through a complete LiveKit room turn. The greeting emitted xAI TTS usage for 43 characters / 3.13 seconds of audio, and a voice prompt traversed STT → LLM → xAI TTS before committing Pooling works. with tts_node_ttfb about 405 ms.

---

Ported from livekit/agents#6393

Original PR description

closes #6390

Cue voice E2E

• Strict voice-mode session: sid_10ecd2a5f336 at head 432b0746.
• A live xAI websocket served four TTS streams across the greeting and three spoken turns; persisted counters reached connectionCount=1, streamCount=4.
• QCLI persisted framework events plus full-session and per-command WAV recordings under ~/.cue-cli/sessions/sid_10ecd2a5f336/.
• The 1,800,000 ms deadline rotation was verified by three deterministic runtime tests rather than holding the live QCLI session open for 30 minutes.

[changeset-bot]

🦋 Changeset detected

Latest commit: 432b074

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

This PR includes changesets to release 36 packages

Name	Type
@livekit/agents-plugin-xai	Patch
@livekit/agents	Patch
@livekit/agents-plugin-anam	Patch
@livekit/agents-plugin-anthropic	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-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-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-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-plugins-test	Patch

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