Boarded in a combined worktree: typecheck:core, check:dashboard-typecheck, check:file-size, check:changelog-integrity, check:complexity, check:cognitive-complexity, check:cycles, check-deps all green. Clean, self-contained addition (5 new files, 0 modifications to existing code) that mirrors the existing dashboard-typecheck baseline-ratchet pattern. Thanks for closing a real coverage gap — API routes had no dedicated typecheck gate.