Retired Action interfaces

The public composite Actions and reusable publisher were retired after native packages became the canonical installation path. New refs do not contain the root, setup, or publish Actions or the repository reusable workflow. Immutable older tags and commit SHAs remain available for historical builds.

On a connected host with Pixi installed, migrate by running:

pixi global install --channel https://prefix.dev/archont561/archont561 --channel conda-forge pixi-sandbox
pixi-sandbox init

Review and commit the generated .github/workflows/publish-sandbox.yml. It installs the same native package and invokes plan, pack, doctor, and publish directly, preserving native matrix, checksum, verification, Cargo-vendor, and orphan-branch coverage without a repository-owned Action.