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

core/home/config/nomarchy/default/bash/envs

@@ -3,5 +3,4 @@ export SUDO_EDITOR="$EDITOR"
 export BAT_THEME=ansi
 
 # Duplicated from .config/uwsm/env so SSH works too
-export NOMARCHY_PATH=$HOME/.local/share/nomarchy
-export PATH=$NOMARCHY_PATH/bin:$PATH:$HOME/.local/bin
+export PATH=$PATH:$HOME/.local/bin

core/home/config/nomarchy/default/elephant/nomarchy_themes.lua

@@ -32,8 +32,8 @@ end
 function GetEntries()
   local entries = {}
   local user_theme_dir = os.getenv("HOME") .. "/.config/nomarchy/themes"
-  local nomarchy_path = os.getenv("NOMARCHY_PATH") or ""
-  local default_theme_dir = nomarchy_path .. "/themes"
+  local nomarchy_path = os.getenv("NOMARCHY_PATH") or "/etc/nixos"
+  local default_theme_dir = nomarchy_path .. "/themes/palettes"
 
   local seen_themes = {}