Set up Samba file share on beryllium over Tailscale

Set up Samba file sharing on beryllium (NixOS) so files in /home/ben/ava can be browsed from other machines on the Tailscale network.

Add to beryllium's NixOS config:

services.samba = {
  enable = true;
  openFirewall = true;
  settings = {
    global = {
      "workgroup" = "WORKGROUP";
      "server string" = "beryllium";
      "security" = "user";
      "map to guest" = "Bad User";
    };
    ava = {
      path = "/home/ben/ava";
      browseable = "yes";
      "read only" = "yes";
      "guest ok" = "yes";
    };
  };
};

Then nixos-rebuild switch. After that, smb://beryllium/ava/ should be browsable from Finder on the Mac.

Read-only guest access is fine since it's only accessible over Tailscale.