56649b428d
Adds fig_theta133.png illustrating the polygon-with-one-chord case: hexagon C_6 with the chord between v_0 and v_3 (the two trivalent vertices), edges colored with a valid proper 3-edge-coloring using the 3 colors a, b, c. Replaces the previous bracketed placeholder text in §6 of menagerie.tex. Adds draw_theta_133.py generator script. Paper stays at 4 pages. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>