Review catches: (1) <<-EOT strips by the closing marker's indent, so the
cloud-config body must match it (2 spaces) for '#cloud-config' to land at column
0; (2) the Hetzner Cloud Firewall filters public traffic, so ssh_admin_cidrs is
ubongo's WAN/egress IP, not its LAN address — a private CIDR would lock SSH out of
the live VPS.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>