Stage 4: Calamares installer and Btrfs snapshots (0.2.0)

- Package Calamares 3.4.3 (Qt6, widgets UI) with xbps-src.
- das-installer: Calamares setup for Void/runit with Das OS branding and
  slides. It copies the clean live image (live-base), builds locales and the
  host-only initramfs, rewrites kernels without sparse tails (GRUB 2.12 cannot
  read Btrfs holes at the end of a file), then removes itself.
- das-snapshots: flat Btrfs layout (@, @home, @snapshots, @var_log,
  @var_cache_xbps), snapper with hourly snapshots via cronie, grub-btrfs menu,
  snapper-rollback, and a dracut module that boots read-only snapshots with
  a RAM overlay.
- das-settings 0.2.0: start LightDM with the system locale.
- Live image: GRUB, efibootmgr and the new packages; Das OS /etc/issue.
- Build: wipe stale destdirs before building packages.

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

srcpkgs/das-snapshots/template

@@ -0,0 +1,20 @@
+# Template file for 'das-snapshots'
+pkgname=das-snapshots
+version=0.1.0
+revision=1
+depends="btrfs-progs cronie dracut grub-btrfs snapper snapper-rollback"
+short_desc="Das OS Btrfs snapshots: snapper setup, boot menu entries and rollback"
+maintainer="Das <anry.das@gmail.com>"
+license="MIT"
+homepage="https://git.das.org.ua/das/Das-OS"
+
+do_install() {
+	vbin ${FILESDIR}/das-snapper-setup
+	vinstall ${FILESDIR}/snapper-root.conf 644 usr/share/das/snapper root
+	vinstall ${FILESDIR}/das-snapshots.conf 644 usr/lib/dracut/dracut.conf.d 50-das-snapshots.conf
+	vinstall ${FILESDIR}/dracut/90das-snapshot-overlay/module-setup.sh 755 \
+		usr/lib/dracut/modules.d/90das-snapshot-overlay
+	vinstall ${FILESDIR}/dracut/90das-snapshot-overlay/das-snapshot-overlay.sh 755 \
+		usr/lib/dracut/modules.d/90das-snapshot-overlay
+	vlicense ${FILESDIR}/LICENSE
+}