Function prepare_owned 

pub async fn prepare_owned<R>(
    pool: &SqlitePool,
    args: R,
    app_config: &BhtuneConfig,
    demo_session_id: i64,
) -> Result<PreparedTune>
where
    R: TryInto<ValidatedTuneRequest>,
    R::Error: Error + Send + Sync + 'static,

Prepare a simulator tune and bind its history to a demo session before the background execution is started. Live OPC DA preparation is intentionally rejected by this helper.