livekit-agents@1.2.15

## What's Changed
* reduce CI noise by @theomonnom in https://github.com/livekit/agents/pull/3552
* automatically update livekit-agents pyproject.toml optional dependencies on version bump by @theomonnom in https://github.com/livekit/agents/pull/3553
* added drain param to session.shutdown() by @tinalenguyen in https://github.com/livekit/agents/pull/3562
* fix stt final transcript triggers user turn in manual turn detection by @longcw in https://github.com/livekit/agents/pull/3559
* feat(livekit-plugins-hume): add model_version parameter by @zgreathouse in https://github.com/livekit/agents/pull/3563
* fix model provider and metrics for FallbackAdapter and StreamAdapter by @longcw in https://github.com/livekit/agents/pull/3526
* handle aiohttp client error when connecting to openai realtime api by @longcw in https://github.com/livekit/agents/pull/3574
* Add `timeout` param to `with_openrouter()` function by @msaelices in https://github.com/livekit/agents/pull/3538
* Add a dev folder for examples to keep the git graph clean by @Shubhrakanti in https://github.com/livekit/agents/pull/3582
* Ensure ctx.api uses WorkerOptions credentials by exporting LIVEKIT_* in worker by @hwuiwon in https://github.com/livekit/agents/pull/3581
* feat(google): Add thinking_config support, new model, and expanded voice profiles for google gemini TTS by @hwuiwon in https://github.com/livekit/agents/pull/3583
* chore: ensure a recent version of certifi is installed by @davidzhao in https://github.com/livekit/agents/pull/3580
* fix(deepgram): correctly handle timeout related errors by @davidzhao in https://github.com/livekit/agents/pull/3579
* realtime model: wait for generate_reply before update tool results by @longcw in https://github.com/livekit/agents/pull/3511
* fix aws realtime deps version by @longcw in https://github.com/livekit/agents/pull/3592
* Updating Cartesia Version by @namantalreja in https://github.com/livekit/agents/pull/3570
* fix: lock pyav to <16 due to build issue by @davidzhao in https://github.com/livekit/agents/pull/3593
* lift google realtime api out of beta by @tinalenguyen in https://github.com/livekit/agents/pull/3614
* catch delete_room errors and disable delete_room_on_close by default by @longcw in https://github.com/livekit/agents/pull/3600
* feat(telemetry/utils): add ttft reporting to LangFuse by @bml1g12 in https://github.com/livekit/agents/pull/3594
* Add RTZR(ReturnZero) STT Plugin for LiveKit Agents by @kimdwkimdw in https://github.com/livekit/agents/pull/3376
* chore: Remove duplicate docstring for `preemptive_generation` parameter in AgentSession by @m-hamashita in https://github.com/livekit/agents/pull/3624
* fix(deepgram): send CloseStream message before closing TTS WebSocket by @Nisarg38 in https://github.com/livekit/agents/pull/3608
* feat(speechmatics): add max_speakers parameter for speaker diarization by @nsepehr in https://github.com/livekit/agents/pull/3524
* Align Google STT plugin with official documentation by @mrkowalski in https://github.com/livekit/agents/pull/3628
* add backwards compatibility for google's realtime model by @tinalenguyen in https://github.com/livekit/agents/pull/3630
* fix: exclude temperature parameter for gpt-5 and similar models by @TheAli711 in https://github.com/livekit/agents/pull/3573
* turn_detection: reduce max_endpointing_delay to 3s by @lwestn in https://github.com/livekit/agents/pull/3640
* feat: Integrate streaming endpoints for Sarvam APIs by @shreyas-sarvam in https://github.com/livekit/agents/pull/3498
* fix: heartbeat by @zachkamran in https://github.com/livekit/agents/pull/3648
* enable zero retention mode in elevenlabs by @tinalenguyen in https://github.com/livekit/agents/pull/3647
* Unprompted STT Reconnection at startup by @adrian-cowham in https://github.com/livekit/agents/pull/3649
* fix #3650 cartesia version backward compatibility by @wlbksy in https://github.com/livekit/agents/pull/3651
* livekit-agents 1.2.15 by @theomonnom in https://github.com/livekit/agents/pull/3658

## New Contributors
* @hwuiwon made their first contribution in https://github.com/livekit/agents/pull/3581
* @namantalreja made their first contribution in https://github.com/livekit/agents/pull/3570
* @kimdwkimdw made their first contribution in https://github.com/livekit/agents/pull/3376
* @m-hamashita made their first contribution in https://github.com/livekit/agents/pull/3624
* @Nisarg38 made their first contribution in https://github.com/livekit/agents/pull/3608
* @nsepehr made their first contribution in https://github.com/livekit/agents/pull/3524
* @TheAli711 made their first contribution in https://github.com/livekit/agents/pull/3573
* @lwestn made their first contribution in https://github.com/livekit/agents/pull/3640
* @shreyas-sarvam made their first contribution in https://github.com/livekit/agents/pull/3498
* @adrian-cowham made their first contribution in https://github.com/livekit/agents/pull/3649

**Full Changelog**: https://github.com/livekit/agents/compare/livekit-agents@1.2.14...livekit-agents@1.2.15