Don't draw the superclass class node when an instance matches locally

Don't draw the superclass class node when an instance matches locally

Previously every "superclass needed" arrow pulled in both the matched
instance node *and* a class node for the superclass — joined to the
matched instance by an extra "defines" edge. The class node duplicated
information already on the matched-instance label, just adding clutter.
Restrict the class-node side to the no-local-match branch, which still
needs somewhere for its needs-external edge to terminate.

Co-Authored-By: Claude Opus 4.7 (1M context) <[email protected]>