* feat(packaging): add AUR release package and CI publish
Ship packaging/aur/vocalinux for yay installs of tagged releases, wire
AUR publish into the release workflow (skipped until secrets are set),
and document one-time maintainer setup.
Fixes#116
* refactor(packaging): slim AUR PR to PKGBUILD + CI
Drop systemd unit, install script, website edits, and long docs.
Keep release PKGBUILD, minimal publish job, and short AUR setup notes.
