apps/api runs ts-jest with isolatedModules: true, which skips cross-file type checking. Task 3 proved the gap concretely: the suite reported 233/234 green while npm run build reported 21 real errors across 6 files. Every full-suite step now runs test && build, with a Global Constraints note explaining why the build half is not redundant. Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>