Function drop_at_end

pub(crate) fn drop_at_end(clip: &Clip, t: f64) -> bool

A transition card dropped on a clip at timeline time t: which of the clip’s two cuts it means. The half you drop on picks it, so the gesture reads the same as “Add at start” / “Add at end”. Shared so the timeline’s drop highlight and the app’s drop handler cannot drift apart.