Old matches stored a DRAW per fighter, but a draw concerns both fighters so
there must be exactly one per match. _run_match_job now dedupes the match's
draws (keeping the first) and persists prompts.json on ANY operation, so a
legacy match self-heals the moment it's touched — regen no longer rewrites a
draw per fighter, and the per-outcome prompt regen targets the single draw.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>