Scaffold BOS repo: dotfiles, ISO profile, and bos-settings GTK4 app

Implements all four components from the BOS spec:
- dotfiles/: default Hyprland, bread, breadbox, breadcrumbs configs
- iso/: archiso profiledef, package list, Calamares YAML modules, post-install.sh
- bos-settings/: Cargo workspace with GTK4 settings app (8 views: snapshots,
  packages, bread, breadbar, breadbox, breadcrumbs, breadpad, hyprland)

https://claude.ai/code/session_01WszGHvCmxgcyTwNSkfLF9P

iso/airootfs/etc/calamares/modules/packages.conf

@@ -0,0 +1,10 @@
+---
+backend: pacman
+
+options:
+  - update_db: true
+
+operations:
+  - try_install:
+    - pipewire-pulse
+    - pipewire-alsa