Each section now starts at the rotation whose vertices line up best with the lead section's, vertex for vertex, instead of at the one vertex closest in direction to the lead's first. Fixes the twisted loft of matching non-convex sections; regression test loft_pairs_the_vertices_of_matching_non_convex_sections.
Session::replace_design keeps auto_project when file.new, doc.open and doc.recover swap in another design, and the UI keeps it across tabs, adopt and the last-tab close. Regression tests in engine (sketch_project) and ui-egui (documents).
HEOJUNFO