feat: add DashScope bidirectional streaming TTS adapter

backend/services/pipecat/service_factory.py

@@ -137,7 +137,7 @@ def create_llm(cfg: AssistantConfig):
 
 
 def create_tts(cfg: AssistantConfig):
-    """CosyVoice 等,走 OpenAI 兼容的 /v1/audio/speech。"""
+    """根据资源的协议创建独立 TTS 服务。"""
     voice = _require(cfg.voice, "TTS voice")
     if cfg.tts_interface_type == "xfyun-super-tts":
         return XfyunSuperTTSService(
@@ -171,7 +171,16 @@ def create_tts(cfg: AssistantConfig):
             push_stop_frames=True,
             stop_frame_timeout_s=WEBSOCKET_TTS_STOP_FRAME_TIMEOUT_S,
         )
-    if cfg.tts_interface_type not in {"openai-tts", "dashscope-tts"}:
+    if cfg.tts_interface_type == "dashscope-tts":
+        from services.pipecat.dashscope_tts import DashScopeTTSService
+
+        return DashScopeTTSService(
+            api_key=_require(cfg.tts_api_key, "TTS apiKey"),
+            model=_require(cfg.tts_model, "TTS modelId"),
+            voice=voice,
+            url=_require(cfg.tts_base_url, "TTS apiUrl"),
+        )
+    if cfg.tts_interface_type != "openai-tts":
         raise ValueError(f"不支持的 TTS 接口类型: {cfg.tts_interface_type}")
 
     # Pipecat 默认只接受 OpenAI 官方音色。OpenAI 兼容服务常使用自定义 voice id,