count_elgs.py enumerates triangulation iso-classes and counts Even Level
Graphs (G,v) per n: iso-classes (sources up to Aut) and flag-rooted
(4E/|Aut| * s, an exact integer since Aut acts freely on flags).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>