Interface ShapeCoversPointOptions

Extra grab distance around the outline, in world units. Callers derive it from a screen-pixel slop and the view scale, the same way affordance hit radii work.

Without slop a hairline is a mathematically zero-width target: the stroke of a 1px outline is half a world unit wide at scale 1, which no one can hit. Defaults to 0 so a caller that hasn't thought about the view still gets exact geometry rather than a wrong guess.