Implement DashScope ASR provider and enhance ASR service architecture

- Added DashScope ASR service implementation for real-time streaming.
- Updated ASR provider logic to support DashScope alongside existing providers.
- Enhanced runtime metadata resolution to include DashScope as a valid ASR provider.
- Modified configuration files and documentation to reflect the addition of DashScope.
- Introduced tests to validate DashScope integration and ASR service behavior.
- Refactored ASR service factory to accommodate new provider options and modes.

api/app/routers/assistants.py

@@ -320,12 +320,17 @@ def _resolve_runtime_metadata(db: Session, assistant: Assistant) -> tuple[Dict[s
     if assistant.asr_model_id:
         asr = db.query(ASRModel).filter(ASRModel.id == assistant.asr_model_id).first()
         if asr:
-            asr_provider = "openai_compatible" if _is_openai_compatible_vendor(asr.vendor) else "buffered"
+            if _is_dashscope_vendor(asr.vendor):
+                asr_provider = "dashscope"
+            elif _is_openai_compatible_vendor(asr.vendor):
+                asr_provider = "openai_compatible"
+            else:
+                asr_provider = "buffered"
             metadata["services"]["asr"] = {
                 "provider": asr_provider,
                 "model": asr.model_name or asr.name,
-                "apiKey": asr.api_key if asr_provider == "openai_compatible" else None,
-                "baseUrl": asr.base_url if asr_provider == "openai_compatible" else None,
+                "apiKey": asr.api_key if asr_provider in {"openai_compatible", "dashscope"} else None,
+                "baseUrl": asr.base_url if asr_provider in {"openai_compatible", "dashscope"} else None,
             }
         else:
             warnings.append(f"ASR model not found: {assistant.asr_model_id}")