feat: install systemd user services to /etc/systemd/user/

- PKGBUILD installs services directly to /etc/systemd/user/ and creates
  WantedBy symlinks (no manual systemctl --user enable needed)
- Install hook cleans up legacy user-level service files from
  ~/.config/systemd/user/

moonarch-git/moonarch.install

@@ -54,11 +54,15 @@ post_install() {
         fi
     fi
 
-    # Cleanup legacy user-level paru config (moved to /etc/paru.conf)
+    # Cleanup legacy user-level configs (moved to system-level)
     while IFS=: read -r _ _ uid _ _ home _; do
         if [ "$uid" -ge 1000 ] && [ "$uid" -lt 60000 ] && [ -d "$home" ]; then
             rm -f "$home/.config/paru/paru.conf" 2>/dev/null || true
             rmdir "$home/.config/paru" 2>/dev/null || true
+            for svc in cliphist kanshi nautilus walker; do
+                rm -f "$home/.config/systemd/user/${svc}.service" 2>/dev/null || true
+                rm -f "$home/.config/systemd/user/graphical-session.target.wants/${svc}.service" 2>/dev/null || true
+            done
         fi
     done < /etc/passwd