Ports ci.yml and publish.yml after the GitHub account was suspended. The
workflow here is identical to the one upstream in ihasmail, so this is the
same pipeline: tests as the image's unprivileged node user, git installed
for the version check, and a tag-driven multi-arch publish under QEMU.
The job environment differences are explained inline -- they are all cases
where a container is not a workstation, not changes to what is tested. No
test was modified.
The Actions workflows stay in the tree as the reference.
