- answers.test.ts: 19 tests covering all 10 checkAnswer() tiers
- scoring.test.ts: 30 tests for scoreRound, calculateElo, calculateTier, applyModifiers
- challenges.test.ts: 16 tests for pickChallenge, type exclusion, data integrity
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>