Add websocket based realtime TTS client (#159)

* feat: adding realtime tts client

* chore: fixed issues

* refactor: remove unused RealtimeClientTTS class and update imports in realtime.py

* fix: update README and scripts to use RealtimeClientASR for WebSocket-based Realtime Transcription; change default server port for TTS client to 9000

* feat: enhance realtime TTS client with parallel processing

* feat: fixed issues

* feat: improve parallel synthesis in realtime TTS client with concurrency control and enhanced logging

* fix: handle exit status in realtime TTS client main function

* fix: update audio handling in realtime TTS client to concatenate audio chunks and ensure proper playback

* fix: correct exit status return value in realtime TTS client main function

* fix: handle error state in realtime TTS client to prevent synthesis continuation on error