CI publishes every locally built apk to the instance's Alpine registry
(catbot credentials via the PACKAGE_TOKEN secret; step skips until it
exists). catcrafts-fp6-repo ships the registry signing key and appends
the repo URL - NOT yet in extra_packages: the registry must have its
first content before image builds may reference it (an empty repo's
missing APKINDEX would break apk in the build chroots).
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
