docs: fix remaining stale references in README and CLAUDE.md

- scripts/: replace update.sh with moonarch-update, fix description
- Update section: remove stale "syncs repo, deploys XDG" claim
- User services: add stasis to table
- CLAUDE.md: mention systemd user services in defaults/ description

CLAUDE.md

@@ -7,7 +7,7 @@ Reproduzierbares Arch-Linux-Setup basierend auf archinstall + Post-Install-Autom
 - `config/` — archinstall-Konfiguration (inkl. custom-commands die das Repo nach /opt/moonarch klonen, root-owned)
 - `scripts/` — Post-Install- und Helper-Scripts
 - `packages/` — Paketlisten (offiziell + AUR), getrennt gepflegt
-- `defaults/` — XDG-Configs, Shell-Config, Helper-Binaries, greetd/moongreet-Config, Wallpaper
+- `defaults/` — XDG-Configs, Shell-Config, Helper-Binaries, systemd User-Services, greetd/moongreet-Config, Wallpaper
 
 ## Konventionen