feat: add script to manage system applications

Introduce a script to organize applications under /Applications/Nix Apps. This setup improves the management and accessibility of system applications by creating aliases for them.

modules/darwin/system/interface/default.nix

@@ -13,6 +13,26 @@ in
     system.defaults = {
       dock.autohide = true;
 
+    system.activationScripts.applications.text = let
+      env = pkgs.buildEnv {
+        name = "system-applications";
+        paths = config.environment.systemPackages;
+        pathsToLink = "/Applications";
+      };
+    in
+      pkgs.lib.mkForce ''
+      # Set up applications.
+      echo "setting up /Applications..." >&2
+      rm -rf /Applications/Nix\ Apps
+      mkdir -p /Applications/Nix\ Apps
+      find ${env}/Applications -maxdepth 1 -type l -exec readlink '{}' + |
+      while read src; do
+        app_name=$(basename "$src")
+        echo "copying $src" >&2
+        ${pkgs.mkalias}/bin/mkalias "$src" "/Applications/Nix Apps/$app_name"
+      done
+          '';
+
       finder = {
         AppleShowAllExtensions = true;
         FXEnableExtensionChangeWarning = false;