forgehand v0.1.1

Dependency and release-hygiene updates; no configuration changes.

- Updates prometheus/client_golang to v1.25.0 and the taskscaler Prometheus metrics module; taskscaler itself is unchanged.
- Each binary's `.sha256` now names the bare file, so `sha256sum -c` passes beside a plain download.
- SECURITY.md: VF `spoofchk` stops MAC spoofing only; ARP and IP protection needs the libvirt plugin's `nwfilter`.
- Releases are now also published on the GitHub mirror.

Install: binaries for linux amd64 and arm64 on this page, or `go install gitlab.com/dunn.dev/forgehand/cmd/forgehand@v0.1.1`. Each binary has a `.sha256` and a cosign `.bundle` in the package registry; see Verify a release in the README.

Before 1.0, a minor release (0.2) may rename, remove or change a configuration key; a patch release (0.1.x) never does. Each break is listed in that release's notes with the change to make.