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).

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

@@ -0,0 +1,28 @@
+# Lock screen (hyprlock). Solid dark background (no runtime-generated wallpaper
+# dependency), accent matched to the Hyprland border colour.
+general {
+    hide_cursor = true
+}
+
+background {
+    monitor =
+    color = rgba(46, 52, 64, 1.0)
+    blur_passes = 0
+}
+
+input-field {
+    monitor =
+    size = 20%, 5%
+    outline_thickness = 3
+    inner_color = rgba(0, 0, 0, 0.2)
+    outer_color = rgba(136, 192, 208, 0.8)
+    check_color = rgba(120, 220, 140, 0.95)
+    fail_color = rgba(255, 90, 90, 0.95)
+    font_color = rgba(255, 255, 255, 0.95)
+    fade_on_empty = false
+    rounding = 12
+    placeholder_text = <i>Password…</i>
+    position = 0, -20
+    halign = center
+    valign = center
+}