scripts/build-and-push.sh now parses ~/.ssh/config (or --ssh-config)
when --remote is a bare alias like 'prod'. It extracts HostName,
User, Port and IdentityFile from the matching Host block, falls back
to the current user / port 22, and uses the config IdentityFile when
--ssh-key is not given. --ssh-key always wins. The resolved target
is shown in the logs before any docker/pussh call, and is the form
passed to docker pussh and the verification ssh.
Wildcards, Include and Match directives are intentionally not handled:
ssh itself resolves them when the alias is passed through, but the
script logs the expanded target first for visibility.