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/profile.d/bos-local-bin.sh

@@ -0,0 +1,9 @@
+# Put the per-user bakery bin dir on PATH. The bread ecosystem (breadd, breadbar,
+# breadbox, …) is installed there by bakery, and the Hyprland session launches
+# them via `exec-once`, which resolves against the PATH it inherits from the
+# login shell. Arch's stock /etc/profile does not add ~/.local/bin, so do it here
+# for every login shell (live user and installed user alike).
+case ":$PATH:" in
+    *":$HOME/.local/bin:"*) ;;
+    *) export PATH="$HOME/.local/bin:$PATH" ;;
+esac