Adds Reinstall method to PackageManager and AURHelper interfaces
so modules can invoke the concrete Reinstall helpers behind the
interface. *Pacman and *Yay already satisfy it.
- neofetch was removed from Arch's official repos; fastfetch is the maintained replacement.
- ExecRunner.Run previously discarded stderr, so any 'sudo pacman' failure surfaced only as 'exit status 1'. Now the returned error includes the captured stderr (matching what Output already did).
- privilege: wire sudo -v to real stdin/stdout/stderr so it can prompt
- cmd: validate --only/--skip IDs against registry (prevents silent
run-all on typo); gate install to Arch-only (spec requirement);
mark --only and --skip mutually exclusive
- platform: Pacman.Update now runs -Syu --noconfirm, not -Sy (avoids
Arch partial-upgrade anti-pattern)
- test/integration: trap-clean the named docker volume on any exit
- go.mod: tidy — yaml.v3 is a direct dep
