user_encrypt_installation.txt does not encrypt anything: encryption is
driven by the disk_encryption block inside user_configuration.json,
which carries the passphrase in plaintext. The flag must match that
block, since it drives the encrypted install's autologin and the final
boot validation. The plan also claimed sshd ships enabled -- it ships
disabled, which is the whole reason the SSH phase exists -- and now
reflects the extracted loader and the unit tests.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
