Function run 

pub fn run(
    specs: Vec<ScenarioSpec>,
    engines: &Arc<Vec<Box<dyn EngineFactory>>>,
    store: &Arc<Mutex<GlobalStore>>,
    config: &RunConfig,
    events: &EventSink,
    cancel: &CancellationToken,
) -> RunSummary

Execute specs and return the summary. Emits the full event stream on events (RunStarted … RunFinished — ADR-0008).