Generated by wave test-gen pipeline. Coverage: - router.js: 0% → ~85% (33 tests, all 7 exports) - sections.js: 0% → ~90% (29 tests, all 5 exports) - renderer.js: partial → extended (36 tests, difficulty, feedback, sidebar) - validator.js: partial → extended (84 tests, all types + edge cases) Total: 43 → 225 tests