fix: Remove invalid global declaration outside function scope

app.py

@@ -2175,9 +2175,6 @@ if __name__ == "__main__":
     server_name = os.getenv("GRADIO_SERVER_NAME", "0.0.0.0")
     server_port = int(os.getenv("PORT", "7860"))
 
-    # Global reference for shutdown handler
-    global conversation_storage
-
     log_startup("=" * 60)
     log_startup("Cain Agent Office Starting...")
     log_startup(f"Server: {server_name}:{server_port}")