Adds extended_deep_embedding (subdividing the outer face with an outer-cap
vertex), quadrilateral_decomposition (pairing faces across level edges),
and quadrilateral_sequencing which runs the anchor drop / level add /
join / ring completion precedence with bottommost-on-the-canonical-
boundary-walk tiebreaks and a lex-smallest move-code-string choice for
the initial quad.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
didericis