修改运行端口尽量避免冲突

backend/main.py

@@ -119,4 +119,4 @@ if frontend_dist.exists():
 
 if __name__ == "__main__":
     import uvicorn
-    uvicorn.run("backend.main:app", host="0.0.0.0", port=8000, reload=True)
+    uvicorn.run("backend.main:app", host="0.0.0.0", port=8021, reload=True)