- Add unique index on (sports_season_id, name) in participants table
- findParticipantByName uses case-insensitive lower() comparison
- Single add: check for existing name before insert, return clear error
- Bulk add: load existing names once upfront (1 query vs N), dedup
input case-insensitively, report skipped names in UI
- Fix golf-skills and surface-elo routes which called createParticipant
without any duplicate guard (would have thrown DB constraint errors)
Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>
