v0.3.2 — a depth limit is not a blind spot

Found while verifying 0.3.1 from PyPI: at a shallow --depth the ?unexposed marker appeared on a node whose children the depth limit had cut. At the depth a snapshot stops, every node looks childless, so the marker there reports the caller's own limit as a property of the application — the same mistake BUG-011 fixed for 'empty', in a feature shipped an hour earlier. The boundary level is no longer marked.