add pipewire.desktop autostart and configure SDDM Wayland compositor

Place pipewire.desktop in root-overlay /etc/skel/.config/autostart/
so PipeWire starts via XDG autostart on login via the patched
artix-pipewire-launcher (now supports dinit in our pipewire fork).

Configure SDDM [Wayland] section with kwin_wayland compositor
command for a Wayland-native greeter display.

Includes:
- buildiso: antergos theme symlinked as artix for prepare_grub
- profile.yaml: dinit-user-spawn -> userspawn-dinit, added
  dbus-dinit-user, pipewire-pulse-dinit, userspawn-dinit to livefs,
  antergos-lsb-release
- services-artix.conf: dinit-user-spawn -> userspawn
- basestrap.conf: xlibre-xserver for online install
- pacman.conf: IgnorePkg xorg-server to avoid conflict with xlibre
- sddm.conf: Wayland compositor command
- common.yaml: cleanup (dedup lsb-release, vi->ex-vi-compat,
  remove artix-grub-theme, jack2, noto-fonts-emoji)
- iso-x86_64.conf: IgnorePkg xorg-server for ISO build

buildiso

@@ -178,9 +178,14 @@ make_grub(){
             layer=${work_dir}/livefs
         fi
 
+        # Ensure artix theme dir exists (prepare_grub hardcodes it)
+        if [[ -d "${work_dir}/rootfs/usr/share/grub/themes/antergos" ]] && [[ ! -d "${work_dir}/rootfs/usr/share/grub/themes/artix" ]]; then
+            cp -r "${work_dir}/rootfs/usr/share/grub/themes/antergos" "${work_dir}/rootfs/usr/share/grub/themes/artix"
+        fi
+
         prepare_grub "${work_dir}/rootfs" "$layer"
 
-        # Copy Antergos GRUB theme to ISO boot (overrides Artix theme)
+        # Also copy as antergos for the installed system
         if [[ -d "${work_dir}/livefs/usr/share/grub/themes/antergos" ]]; then
             cp -r "${work_dir}/livefs/usr/share/grub/themes/antergos" "${iso_root}/boot/grub/themes/"
         elif [[ -d "${work_dir}/rootfs/usr/share/grub/themes/antergos" ]]; then