Fix prod-readiness issues flagged in audit

- Fix XDG config dir logic in config/mod.rs (was double-nesting and had /home/user hardcode)
- Replace /home/user hardcodes in breadbar.rs and hyprland.rs with config::config_dir()
- Fix /home/user hardcode in packages.rs (uses /root fallback for .local/state path)
- Remove eprintln! from GTK callback in packages.rs (no stderr at runtime)
- Fix YAML parse error in branding.desc (missing space after sidebarTextHighlight key)
- Add .gitignore (Rust target/, ISO artifacts, editor/OS junk, secrets)
- Delete state.rs (dead code — never mod'd in main.rs)
- Add brightnessctl, grim, slurp to packages.x86_64 (used by keybinds)
- Rename can-you-begin-a-composed-beacon.md → DESIGN.md

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

bos-settings/src/ui/views/breadbar.rs

@@ -3,10 +3,10 @@ use gtk4::{Box as GBox, Button, Label, Orientation, ScrolledWindow, TextView};
 use std::path::PathBuf;
 
 fn css_path() -> PathBuf {
-    let home = std::env::var("HOME").unwrap_or_else(|_| "/home/user".to_string());
-    PathBuf::from(home).join(".config/breadbar/style.css")
+    crate::config::config_dir().join("breadbar/style.css")
 }
 
+
 pub fn build() -> GBox {
     let path = css_path();
     let existing_css = std::fs::read_to_string(&path).unwrap_or_default();