82fa584cbb
Introduces AchievementContext (stats + last-win snapshot), AchievementDef, ALL_ACHIEVEMENTS, and check_achievements. Adds undo_count to GameState so the no_undo and speed_and_skill conditions are evaluable. Skipped achievements that depend on features not yet built: daily_devotee (progress), comeback (recycle counter), zen_winner (modes), perfectionist (max-score calc). They land in later phases. Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>