feat(upstream): switch to remote git repository for engine

- Update installer to use git+https://git.bemagri.xyz/bernardo/Nomarchy.git
- Remove redundant bundling/copying of the engine to /etc/nixos/nomarchy
- Expose all themes via xdg.dataFile for script accessibility
- Update theme scripts to resolve directories via local share instead of hardcoded system paths
- Update documentation to reflect the new remote-first architecture

modules/home/theme-switcher.nix

@@ -32,19 +32,17 @@ let
   nomarchy-wallpaper-selector = pkgs.writeShellScriptBin "nomarchy-wallpaper-selector" ''
     STATE_DIR="$HOME/.config/home-manager"
     STATE_FILE="$STATE_DIR/state.json"
-    if [ -d "/etc/nixos/nomarchy/themes" ]; then
-      THEMES_DIR="/etc/nixos/nomarchy/themes"
-    elif [ -d "/etc/nomarchy/themes" ]; then
-      THEMES_DIR="/etc/nomarchy/themes"
-    else
-      THEMES_DIR="/etc/nixos/themes"
-    fi
+    THEMES_DIR="$HOME/.local/share/nomarchy/themes"
     
     mkdir -p "$STATE_DIR"
     [[ ! -f $STATE_FILE ]] && echo "{}" > "$STATE_FILE"
     
     # List all images in all themes backgrounds
     WALLPAPERS=$(find "$THEMES_DIR" -type f \( -name "*.jpg" -o -name "*.png" \))
+    # Include user themes if they exist
+    if [ -d "$HOME/.config/nomarchy/themes" ]; then
+        WALLPAPERS="$WALLPAPERS\n$(find "$HOME/.config/nomarchy/themes" -type f \( -name "*.jpg" -o -name "*.png" \))"
+    fi
     SELECTED_WP=$(echo -e "$WALLPAPERS" | walker --dmenu)
     
     if [ -n "$SELECTED_WP" ]; then