Add support for Xfyun ASR and TTS services in the backend

- Introduce new Xfyun ASR and TTS services, enabling integration with iFlytek's voice recognition and synthesis capabilities.
- Update AssistantConfig model to include interface types for STT and TTS.
- Enhance credential testing to validate Xfyun credentials.
- Modify service factory to create Xfyun services based on configuration.
- Update README with new configuration details for Xfyun integration.
- Add new frontend components for visualizing audio streams and managing user interactions.

backend/requirements.txt

@@ -2,7 +2,7 @@
 # webrtc  -> SmallWebRTCTransport / SmallWebRTCConnection + aiortc
 # silero  -> 本地 VAD(判断用户说话起止),语音必备
 # openai  -> OpenAI 兼容的 LLM/STT/TTS 客户端(DeepSeek、SenseVoice、CosyVoice 都走它)
-pipecat-ai[webrtc,silero,openai]~=0.0.60
+pipecat-ai[webrtc,websocket,silero,openai]==1.3.0
 
 fastapi
 httpx
@@ -10,6 +10,7 @@ uvicorn[standard]
 python-dotenv
 pydantic
 loguru
+websockets>=13
 
 # 存储:Postgres(SQLAlchemy 2.0 异步 + asyncpg 驱动)
 sqlalchemy[asyncio]>=2.0