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>

.gitignore

@@ -0,0 +1,37 @@
+# Rust build artifacts
+/target/
+**/*.pdb
+
+# Editor / IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+.direnv/
+
+# OS artifacts
+.DS_Store
+Thumbs.db
+desktop.ini
+
+# Environment / secrets
+.env
+.env.local
+*.env.*
+secrets/
+*.pem
+*.key
+*.p12
+
+# archiso build artifacts (these are large and reproducible)
+/iso-build/
+/iso-out/
+*.iso
+*.img
+
+# Runtime / logs
+*.log
+logs/
+*.pid
+*.sock