Enhance voice interaction features and introduce voice preview functionality

- Update README to reflect the integration of the DebugVoicePanel with WebSocket support for voice interactions.
- Refactor voice_webrtc.py to improve error handling during WebRTC signaling and include assistant_id in the offer payload.
- Add useVoicePreview hook to manage microphone access and WebRTC connections for real-time voice previews.
- Modify AssistantPage to incorporate new visualizer options and pass assistantId to DebugVoicePanel, enhancing user experience during audio interactions.
- Update API model to include new fields for voice, speed, and language, supporting TTS and ASR configurations.

backend/README.md

@@ -100,5 +100,5 @@ docker compose --profile remote up -d
 - [ ] `pip install` 后跑通,核对 pipecat 版本的服务/transport 构造参数(代码内有注释)
 - [ ] 起本地 SenseVoice / CosyVoice 的 OpenAI 兼容服务
 - [ ] `realtime` 模式(目前只 `pipeline` 级联)
-- [ ] 前端 `DebugVoicePanel` 接 `/ws/voice`(抄 dograh `useWebSocketRTC.tsx`)
+- [x] 前端 `DebugVoicePanel` 接 `/ws/voice`(参考 dograh `useWebSocketRTC.tsx`)
 - [ ] 加 DB 后:助手配置入库(目前随请求内联)

backend/routes/voice_webrtc.py

@@ -2,9 +2,10 @@
 
 参考 dograh 的 webrtc_signaling.py,砍掉鉴权/配额/DB/org/ICE 过滤策略/TURN。
 握手消息:
-    client → {type:"offer",         payload:{pc_id, sdp, type, config}}
+    client → {type:"offer",         payload:{pc_id, sdp, type, assistant_id}}
     server → {type:"answer",        payload:{pc_id, sdp, type}}
     both   → {type:"ice-candidate", payload:{pc_id, candidate:{...}}}
+    server → {type:"error",         payload:{message}}
 """
 
 import asyncio
@@ -36,10 +37,22 @@ async def voice_signaling(websocket: WebSocket):
     try:
         while True:
             message = await websocket.receive_json()
-            if message.get("type") == "offer":
-                await _handle_offer(websocket, message.get("payload", {}), peers)
-            elif message.get("type") == "ice-candidate":
-                await _handle_ice(message.get("payload", {}), peers)
+            try:
+                if message.get("type") == "offer":
+                    await _handle_offer(websocket, message.get("payload", {}), peers)
+                elif message.get("type") == "ice-candidate":
+                    await _handle_ice(message.get("payload", {}), peers)
+            except Exception as e:
+                logger.exception(f"处理 WebRTC 信令消息失败: {e}")
+                if websocket.application_state == WebSocketState.CONNECTED:
+                    await websocket.send_json(
+                        {
+                            "type": "error",
+                            "payload": {
+                                "message": f"语音会话启动失败: {type(e).__name__}"
+                            },
+                        }
+                    )
     except WebSocketDisconnect:
         logger.info("WebRTC 信令断开")
     except Exception as e: