feat: 扩展后端WebSocket处理

- 优化api/routers/websocket.py

Co-authored-by: Cursor <cursoragent@cursor.com>

api/routers/websocket.py

@@ -30,6 +30,7 @@ class MessageType(str, Enum):
     CONNECT = "connect"
     AUDIO_CHUNK = "audio_chunk"
     AUDIO_MESSAGE = "audio_message"  # 完整音频消息（类似微信语音）
+    TRANSCRIBE_ONLY = "transcribe_only"  # 仅转写，不落库、不触发 Agent，用于「转文字」发送
     TEXT = "text"  # 文本消息
     TRANSCRIPT = "transcript"  # 语音转文字结果
     AGENT_RESPONSE = "agent_response"
@@ -280,6 +281,33 @@ async def websocket_endpoint(
                                     "timestamp": datetime.now(timezone.utc).isoformat()
                                 })
                     
+                    elif msg_type == MessageType.TRANSCRIBE_ONLY:
+                        # 仅转写：不落库、不触发 Agent，用于客户端「转文字」后发文本
+                        data = message.get("data", {})
+                        audio_base64 = data.get("audio_base64", "")
+                        if not audio_base64:
+                            await manager.send_message(conversation_id, {
+                                "type": MessageType.ERROR,
+                                "data": {"message": "缺少 audio_base64"},
+                                "timestamp": datetime.now(timezone.utc).isoformat()
+                            })
+                            continue
+                        try:
+                            transcript_text = await asr_service.transcribe(audio_base64)
+                            await manager.send_message(conversation_id, {
+                                "type": MessageType.TRANSCRIPT,
+                                "conversation_id": conversation_id,
+                                "data": {"text": transcript_text or ""},
+                                "timestamp": datetime.now(timezone.utc).isoformat()
+                            })
+                        except Exception as e:
+                            logger.error(f"仅转写失败: {e}", exc_info=True)
+                            await manager.send_message(conversation_id, {
+                                "type": MessageType.ERROR,
+                                "data": {"message": f"转写失败: {str(e)}"},
+                                "timestamp": datetime.now(timezone.utc).isoformat()
+                            })
+                    
                     elif msg_type == MessageType.END_CONVERSATION:
                         # 结束对话
                         conversation.status = "ended"