nixos/tailscale: run `tailscale up` when in Stopped status

            if [[ "$state" != "$lastState" ]]; then

              # https://github.com/tailscale/tailscale/blob/v1.72.1/ipn/backend.go#L24-L32

              case "$state" in

                NeedsLogin)

                NeedsLogin|NeedsMachineAuth|Stopped)

                  echo "Server needs authentication, sending auth key"

                  tailscale up --auth-key "$(cat ${cfg.authKeyFile})${params}" ${escapeShellArgs cfg.extraUpFlags}

                  ;;