- api/game.php: ELO rating update after bot games (K-factor from DB), XP awards
  (50/game + 30 win bonus), level-up detection, economy transaction logging,
  game stats (total_games_played, wins/draws/losses)
- api/daily-reward.php: XP award (25/claim), level-up check, economy tx logging
- api/shop.php: rewritten to use correct tables (cosmetics + player_cosmetics),
  equip/unequip support, feature flag check, economy tx logging
- api/friends.php: notifications on friend request sent/accepted
- api/matchmaking.php: notifications on match found, feature flag check
- api/bots.php: feature flag check (bot_games_enabled)
- config/database.php: added check_feature_flag() helper
- includes/feature-flags.php: new cached feature flag system (60s file cache)
- includes/header.php: includes feature-flags.php
- pages/shop.php: updated to use cosmetic_type enums, equip UI
- templates/nav-*.php: hide disabled features (shop, tournaments)
- DB: seeded 25 achievements, 11 cosmetics, 1 test tournament, disabled trivia
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>