fixes for onboarding aarch64-darwin

apps/loadkey.nix

@@ -5,6 +5,7 @@
   program = builtins.toString (pkgs.writeShellScript "loadkey" ''
     printf "\nEnter the seed phrase for your SSH key...\n"
     printf "\nThen press ^D when complete.\n\n"
+    mkdir -p ~/.ssh/
     ${pkgs.melt}/bin/melt restore ~/.ssh/id_ed25519
     printf "\n\nContinuing activation.\n\n"
   '');