Challenges API now counts actual matches played today:
- games_played: total completed matches today
- wins: matches won today
- chess_played: chess games today
- ludo_played: ludo games today
- domino_played: domino games today
- bot_wins: bot games won today

Progress is calculated server-side by querying matches table
where player was white/black AND status=completed AND created today.
Challenge marked completed=true when progress >= target.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>