Auto-collapse a match's draw outcome(s) to a single canonical draw owned by
f1 with f2 as opponent (representing both fighters), preferring an existing
f1-owned draw so its rendered files survive. Fixes legacy per-fighter draws
and the lone-f2 self-opponent case; lets the draw be regenerated on its own.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>