STT:
- Add Settings class alias and 4-step init pattern
- Add resampler to convert pipeline audio to 16kHz for Together API
- Add keepalive support and _update_settings with reconnect
- Pass language to transcription frames
- Remove unnecessary OpenAI-Beta header
TTS:
- Add Settings class alias and 4-step init pattern
- Use push_start_frame=True for base class audio context management
- Route audio through append_to_audio_context instead of push_frame
- Track pending commits for proper audio context lifecycle
- Replace _handle_interruption with on_audio_context_interrupted
- Add _update_settings with reconnect
- Guard against stale audio after interruption
