Touching sews now split 4-use straight edges on extruded walls (along their rulings), not only on planes. Faces round such an edge are ordered by the way they leave it and, where they leave it tangent, by their curvature. Sheets bound the material wedges as before, except where that would make a face touch itself (a hole touching the outline from inside); edges ending there pair the empty wedges instead, so each loop gets its own vertex. Coincident faces are still refused, plain sew still refuses vertex contact, and shell_groups is unchanged.
A Ø10 hole tangent inside a stepped Ø40/Ø20 boss now cuts exactly instead of failing with "wire is not simple". Robustness seeds 42 and 51 are recorded: their touching hole patterns in stepped bodies now cut exactly instead of by a tool nudge.
Co-authored-by: froglemonade2 <[email protected]>
