Initial Das OS 0.1.0: Void Linux live ISO with Xfce

- xbps-src templates: das-theme (adw-gtk3-based GTK themes, generated
  xfwm4 frames, wallpapers, logo), das-settings (Xfce, panel, LightDM
  defaults in /etc/xdg/das), adw-gtk3 and font-jetbrains-mono
- void-mklive profile in live/: packages, runit services, rootfs overlay,
  Ukrainian locale, live user with autologin
- Void builder container, build scripts, QEMU runner and Makefile
- Bilingual README with screenshots

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

srcpkgs/das-settings/files/profile.d/das-xdg.sh

@@ -0,0 +1,6 @@
+# Das OS desktop defaults (/etc/xdg/das) take precedence over the stock Xfce ones in /etc/xdg.
+# LightDM sources /etc/profile before the session starts, and startxfce4 keeps this order.
+case ":${XDG_CONFIG_DIRS:-}:" in
+  *:/etc/xdg/das:*) ;;
+  *) export XDG_CONFIG_DIRS="/etc/xdg/das:${XDG_CONFIG_DIRS:-/etc/xdg}" ;;
+esac