CLAUDE.md said "fmt is intentionally not gated yet" — stale; the gate is now fmt + clippy + test (ADR-ci-002 Amendment 1 / issue #35), run via `nix develop -c`. Add CI-exact local-verification guidance and flag the exit-code-vs-piped-output trap that masked the fmt failure this session. handoff-79 records the blob removal + the CI/fmt lesson.