Replace github.server_url/GITHUB_REF_NAME with explicit forge URL
and GITEA_REF_NAME/GITEA_OUTPUT.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
On tag push (v*), zips the package and publishes to the
forge.lthn.ai Composer package registry.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>