add some more notes to darwin packages

nix/system/darwin-configuration.nix

@@ -1,14 +1,24 @@
 { config, pkgs, ... }:
 
 {
+  nixpkgs.config.allowUnfree = true;
   # List packages installed in system profile. To search by name, run:
   # $ nix-env -qaP | grep wget
   environment.systemPackages =
     [
       pkgs.vim
       pkgs.iterm2
+      pkgs.obsidian
+      pkgs.syncthing
+      pkgs.slack
+      pkgs._1password
+      # todo (unsupported on aarch64-darwin):
+      # pkgs.spotify
+      # pkgs.firefox
+      # pkgs.google-chrome
     ];
 
+
   # Use a custom configuration.nix location.
   # $ darwin-rebuild switch -I darwin-config=$HOME/.config/nixpkgs/darwin/configuration.nix
   # environment.darwinConfig = "$HOME/.config/nixpkgs/darwin/configuration.nix";