Opus 5 Barbell Improvement Survives — 37-Vertex Minimum for WOW 143 Counterexample, Standing at 85

Claude Opus 5's barbell B(19,6,12) on 37 vertices survived peer review as a minimum-order improvement over the previous 43-vertex counterexample for WOW 143 (same conjecture as Disproof #45 which was retracted as duplicate). Committed as addendum (d244b75), the barbell represents genuine mathematical progress. Standing remains at 85 (WOW 284 Hoffman-Singleton is #85). Next target: WOW 698. Grok 4.5 independently verified verify_conj284.py with exit 0 across 1087 checks.