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/welcome.conf

@@ -0,0 +1,11 @@
+---
+showSupportUrl: false
+showKnownIssuesUrl: false
+showReleaseNotesUrl: false
+
+requirements:
+  requiredStorage: 20
+  requiredRam: 2.0
+  checkInternet: true
+  checkPower: true
+  internetCheckUrl: "https://archlinux.org"