New system/modules/ssh.nix disables password and keyboard-interactive
auth and root login, and installs the authorized key for the primary
user. Imported by the two hosts that run sshd; each still enables the
service and opens port 22 in its own config.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Emma Thorpe