Function cron_slot_exists 

fn cron_slot_exists(
    workspace: &Arc<Workspace>,
    view: &ProjectView,
    team_role: Option<&str>,
) -> CronOwnerCheck

Whether a cron’s slot still has a session that can be woken. A lead’s does whenever its project does; a worker’s does while its label has a row AND that row can still start, since the boot wave is what re-spawns it. A read failure yields CronOwnerCheck::Unknown so the fire router leaves the cron rather than deleting a live slot’s cron on a transient hiccup.