Add Zsh shell to Darwin services and setup Harald's dev environment

Add Zsh to the list of available shells in the Darwin services module.
Introduce new Nix configurations for aarch64-darwin, including system packages and font settings.
Set up user-specific environment for Harald on aarch64-darwin system.

homes/aarch64-darwin/harald@m4/default.nix

@@ -0,0 +1,32 @@
+{
+  lib,
+  pkgs,
+  config,
+  ...
+}:
+{
+  home = {
+    username = "harald";
+    homeDirectory = "/Users/${config.home.username}";
+    stateVersion = "23.11"; # Please read the comment before changing.
+    # sessionPath = [ "$HOME/bin" ];
+  };
+
+  metacfg = {
+
+    cli-apps = {
+      bash.enable = true;
+      fish.enable = true;
+      #neovim.enable = true;
+      bat.enable = true;
+      starship.enable = true;
+      #home-manager.enable = true;
+    };
+
+    tools = {
+      direnv.enable = true;
+      ssh.enable = true;
+      git.enable = true;
+    };
+  };
+}