Make BOS a complete, bootable, themed desktop OS

Install/boot reliability:
- Use native Calamares initcpiocfg/initcpio + explicit grub-install (nvram +
  --removable) in post-install; drop the flaky native bootloader/grubcfg modules.
- mount.conf: bind /proc /sys /dev (devtmpfs) /run + efivars into the chroot.
- bos-copy-kernel: stage kernel + write a stock mkinitcpio preset (replace the
  archiso preset). Per-service systemctl enable (fixes NetworkManager et al.
  silently not enabling due to the all-or-nothing grub-btrfs.path name).

System completeness:
- greetd + tuigreet graphical login; installed pacman.conf + working mirrorlist;
  base CLI tools (nano, micro, vim, htop, …); amd/intel-ucode; tlp + hypridle
  power management; systemd-timesyncd, fstrim.timer; wpa_supplicant wifi; Zen
  browser (republished to the [Breadway] repo).

Desktop + theming:
- Native Lua Hyprland config (hyprland.lua) with curated standard binds; kitty
  (blur) replaces foot; awww wallpaper + pywal palette (tamed to a black base
  with warm accents); GTK dark mode.
- Plymouth boot splash (bos theme: logo + spinner + status) via plymouthcfg.
- Varela Round font; Calamares bread-palette sidebar (logo/black-region polish
  still pending).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

iso/airootfs/etc/skel/.config/hypr/hypridle.conf

@@ -0,0 +1,37 @@
+# Idle management (hypridle). Conservative, mainstream-OS-like defaults:
+# dim -> screen off -> lock -> suspend, all respecting idle inhibitors (so media
+# playback, etc. won't dim or suspend the machine). Vendor-neutral: nothing here
+# is Intel/AMD specific.
+general {
+    lock_cmd         = pidof hyprlock || hyprlock
+    before_sleep_cmd = loginctl lock-session
+    after_sleep_cmd  = hyprctl dispatch dpms on
+    ignore_dbus_inhibit = false
+}
+
+# Dim the backlight after 5 minutes (restored on activity). No-op on hardware
+# without a backlight (desktops / VMs).
+listener {
+    timeout    = 300
+    on-timeout = brightnessctl -s set 10%
+    on-resume  = brightnessctl -r
+}
+
+# Turn the display off after 8 minutes.
+listener {
+    timeout    = 480
+    on-timeout = hyprctl dispatch dpms off
+    on-resume  = hyprctl dispatch dpms on
+}
+
+# Lock shortly after the screen turns off.
+listener {
+    timeout    = 510
+    on-timeout = loginctl lock-session
+}
+
+# Suspend after 20 minutes of inactivity (skipped while something inhibits idle).
+listener {
+    timeout    = 1200
+    on-timeout = systemctl suspend
+}