`gha-expression-proof` is intentionally small and conformance-focused. Changes should improve compatibility with GitHub Actions expression behavior, receipt clarity, or offline CI ergonomics.
Before opening a change, run:
```powershell
cargo fmt --check
cargo test --locked
cargo clippy --locked --all-targets --all-features -- -D warnings
cargo doc --locked --no-deps
```
When changing expression behavior, add a unit or CLI test that names the GitHub Actions behavior being modeled.