Implement StepFun Realtime service and enhance AssistantConfig

- Add new fields to AssistantConfig for realtime interface configuration, including types, values, and secrets.
- Introduce StepFunRealtimeService to handle speech-to-speech processing via WebSocket, integrating STT, LLM, and TTS functionalities.
- Refactor pipeline execution to support a new realtime mode, allowing direct text input processing and immediate responses.
- Update model resource testing to include validation for StepFun Realtime connections.
- Enhance service factory to create realtime services based on configuration settings.
- Modify README documentation to reflect new realtime capabilities and usage instructions.

backend/routes/model_registry.py

@@ -59,6 +59,15 @@ def _resource_out(row: ModelResource) -> ModelResourceOut:
     )
 
 
+async def _commit_resource(
+    session: AsyncSession, row: ModelResource
+) -> ModelResourceOut:
+    """Commit and reload server-generated fields before serializing the row."""
+    await session.commit()
+    await session.refresh(row)
+    return _resource_out(row)
+
+
 async def _definition(
     session: AsyncSession, interface_type: str
 ) -> InterfaceDefinition:
@@ -141,8 +150,7 @@ async def create_model_resource(
             .where(ModelResource.capability == row.capability, ModelResource.id != row.id)
             .values(is_default=False)
         )
-    await session.commit()
-    return _resource_out(row)
+    return await _commit_resource(session, row)
 
 
 @router.post("/model-resources/test", response_model=ModelResourceTestResult)
@@ -196,8 +204,7 @@ async def duplicate_model_resource(
         is_default=False,
     )
     session.add(row)
-    await session.commit()
-    return _resource_out(row)
+    return await _commit_resource(session, row)
 
 
 @router.put("/model-resources/{resource_id}", response_model=ModelResourceOut)
@@ -224,8 +231,7 @@ async def update_model_resource(
             .where(ModelResource.capability == row.capability, ModelResource.id != row.id)
             .values(is_default=False)
         )
-    await session.commit()
-    return _resource_out(row)
+    return await _commit_resource(session, row)
 
 
 @router.delete("/model-resources/{resource_id}")

backend/routes/voice_webrtc.py

@@ -58,7 +58,9 @@ async def voice_signaling(websocket: WebSocket):
     except Exception as e:
         logger.error(f"WebRTC 信令出错: {e}")
     finally:
-        for pc in peers.values():
+        # disconnect() triggers the registered closed callback, which removes
+        # the peer from this dict. Iterate over a snapshot to avoid mutation.
+        for pc in list(peers.values()):
             await pc.disconnect()