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/calamares/modules/mount.conf

@@ -8,3 +8,32 @@ mountOptions:
     options: [noatime, "compress=zstd", "space_cache=v2"]
   - filesystem: vfat
     options: [umask=0077]
+
+# API filesystems mounted into the target so chroot steps work. Without these
+# the chroot has no /proc or /dev and `mkinitcpio` aborts ("/proc must be
+# mounted!" / "/dev must be mounted!") and grub-install can't probe properly.
+# All are real-fs mounts (not bind) — Calamares 3.4.2 here applies fs-type mounts
+# reliably but not bind-type ones, so /dev uses a fresh devtmpfs (which still
+# exposes all device nodes). extraMountsEfi adds efivars on UEFI so grub-install
+# can write an NVRAM boot entry.
+extraMounts:
+  - device: proc
+    fs: proc
+    mountPoint: /proc
+  - device: sys
+    fs: sysfs
+    mountPoint: /sys
+  - device: udev
+    fs: devtmpfs
+    mountPoint: /dev
+  - device: devpts
+    fs: devpts
+    mountPoint: /dev/pts
+  - device: tmpfs
+    fs: tmpfs
+    mountPoint: /run
+
+extraMountsEfi:
+  - device: efivarfs
+    fs: efivarfs
+    mountPoint: /sys/firmware/efi/efivars