### Summary of Changes - Added systemd drop-in override `/etc/systemd/system/ssh.service.d/10-generate-host-keys.conf` with `ExecStartPre=-/usr/bin/ssh-keygen -A` so `ssh.service` auto-generates host keys if missing on startup. - Added `ssh-keygen -A` to `03-cleanup.sh` and `bootstrap-cluster.sh` in `user-data.template.yaml`.