feat: update FastAPI configuration to use settings for host and port

- Refactored the FastAPI server initialization to retrieve host and port from the new settings in envs.py.
- Added BACKEND_HOST and BACKEND_PORT fields to the Settings class for better configuration management.

app.py

@@ -495,7 +495,9 @@ if __name__ == "__main__":
     # Backend server - 在单独的线程中运行
     app = create_app()
 
-    def run_fastapi(host: str = "127.0.0.1", port: int = 8000):
+    def run_fastapi():
+        host = settings.BACKEND_HOST
+        port = settings.BACKEND_PORT
         print(f"Starting FastAPI server on http://{host}:{port}")
         uvicorn.run(
             app,

src/envs.py

@@ -22,6 +22,9 @@ class Settings(BaseSettings):
         Field("y-playground"),
     ]
 
+    BACKEND_HOST: Annotated[str, Field("127.0.0.1", description="Backend host")]
+    BACKEND_PORT: Annotated[int, Field(8000, description="Backend port")]
+
     @computed_field
     @cached_property
     def REPO_ID(self) -> str: