move session handlers inside Blocks context

app.py

@@ -421,6 +421,10 @@ def create_interface():
         model_status = "ℹ️ Models will be loaded on demand"
 
     with gr.Blocks(css=css) as demo:
+        # Move session handlers INSIDE the Blocks context
+        demo.load(fn=start_session)
+        demo.unload(fn=end_session)
+        
         gr.Info(model_status)
         
         # State for storing 3D model data
@@ -580,11 +584,8 @@ def create_interface():
         #     outputs=[download_gs, message_box]
         # )
 
-    # Handlers
-    demo.load(start_session)
-    demo.unload(end_session)
-    
-    return demo 
+    # Don't put any demo.* method calls here outside the Blocks context
+    return demo
 
 if __name__ == "__main__":
     # Initialize models if PRELOAD_MODELS is True