Function handle_dictate_stop 

pub(crate) async fn handle_dictate_stop(
    ws: &Arc<Workspace>,
    key: &SessionSlot,
    submit: bool,
    initiator: Option<u64>,
)

Command::DictateStop: submit (true) or abandon the take that key started. A stop that arrives before its start has registered is parked in stop_pending for the registration to honour, rather than dropped: dropping it would orphan a take until the take’s own cap ended it. A stop whose take already resolved parks too - the park cannot tell the two apart on arrival - but it is only honoured while fresh, and every take-resolution path clears it, so it never poisons the session’s next attempt.