actions/setup-python can only install Python on GitHub's Ubuntu images,
so it fails on this runner's job image ("version 3.12 ... was not found
for this operating system"). Every Gitea runner has Node, since it runs
JavaScript actions, so port the publisher to a dependency-free Node
script (fetch/FormData/Blob) and drop the setup step. Behaviour is
unchanged.
Co-Authored-By: Claude Opus 5.5 <[email protected]>
