* test: reproduce #268 (Panic from truck-topology lib.rs:186 when joining struts that end on a bore wall) * Sew refuses edges whose ends weld to one vertex (#268) The sewer welds vertices on a 1e-6 grid but only rejected edges shorter than 1e-9, so a sliver edge between the two welded its ends into one vertex and truck-topology panicked ("Two same vertices cannot construct an edge") inside the guard. Such an edge is now a degenerate-edge error before any truck call, and the boolean takes its usual fallback. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> --------- Co-authored-by: bherbruck <brennen.herbruck@gmail.com> Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>