rune v0.4.1

CI hardening -- no functional changes from v0.4.0.

- deny.toml: cargo-deny license allow-list (MIT, Apache-2.0, BSD, ISC, MPL-2.0)
- Pipeline v2.1.0: all images from nomograph container registry, no Docker Hub
- Release page includes tag annotation body + mise/manual install instructions
- audit_allow_failure: false (deny config makes audit pass cleanly)
- Updated yanked fastrand 2.4.0 -> 2.4.1
- Cargo.toml version matches tag (--version reports correctly)