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

bos-settings/src/config/mod.rs

@@ -0,0 +1,24 @@
+use std::error::Error;
+use std::path::Path;
+
+pub fn load<T: for<'de> serde::Deserialize<'de>>(path: &Path) -> Result<T, Box<dyn Error>> {
+    let text = std::fs::read_to_string(path)?;
+    Ok(toml::from_str(&text)?)
+}
+
+pub fn save<T: serde::Serialize>(path: &Path, val: &T) -> Result<(), Box<dyn Error>> {
+    if let Some(parent) = path.parent() {
+        std::fs::create_dir_all(parent)?;
+    }
+    std::fs::write(path, toml::to_string_pretty(val)?)?;
+    Ok(())
+}
+
+pub fn config_dir() -> std::path::PathBuf {
+    dirs_path()
+}
+
+fn dirs_path() -> std::path::PathBuf {
+    let home = std::env::var("HOME").unwrap_or_else(|_| "/root".to_string());
+    std::path::PathBuf::from(home).join(".config")
+}