Thin extrude caps are certified by the curves the wall follows, so a sketch attached to a cap survives switching between solid and thin (#1519).
Co-Authored-By: Philipp Bischoff <PhilippBischoff0@users.noreply.github.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Thin Extrude builds walls of a set thickness along sketch curves, open chains and closed loops, with the wall centred, inside, outside or on both sides at two thicknesses. Saved under format 20 (thin on an Extrude); an extrude without thin saves as before. Closes#721.
