remove redundant demo launch and session management calls from main execution block

app.py

@@ -515,12 +515,6 @@ def create_interface():
 
     return demo
 
-if __name__ == "__main__":
-    demo = create_interface()
-    demo.launch()
-    demo.load(start_session)
-    demo.unload(end_session)
-```
 
 if __name__ == "__main__":
     # Initialize the Trellis pipeline before creating the interface