fix(distro): fix /etc/nixos ownership, theme discovery, and CLI wrappers

- installer: set recursive ownership of /etc/nixos to main user post-install
- themes: fix NOMARCHY_PATH and discovery logic for Lua theme menu
- scripts: update CLI wrappers (font, theme, wallpaper) to use Walker menus
- core: remove obsolete NOMARCHY_PATH and cleanup dead code
- features: add pkgs.lua for Walker and remove obsolete switcher.nix
- docs: update ROADMAP.md, SCRIPTS.md and STRUCTURE.md

features/scripts/utils/nomarchy-font

@@ -15,6 +15,9 @@ case "$COMMAND" in
         nomarchy-font-list
         ;;
     selector|*)
-        nomarchy-font-selector
+        theme=$(echo -e "$(nomarchy-font-list)" | nomarchy-launch-walker --dmenu --width 350 -p "Font...")
+        if [[ -n "$theme" && "$theme" != "CNCLD" ]]; then
+            nomarchy-font-set "$theme"
+        fi
         ;;
 esac