Replace single deploy/haproxy.cfg with deploy/haproxy/{haproxy.cfg,challenge.html}.
HAProxy now runs a WebCrypto-based proof-of-work challenge using a stick-table,
URI normalization and a challenge backend. docker-compose mounts the haproxy
directory, and also switches the site DB volume to ./db to be consistent. Update robots.txt.ts to
add a honeypot path for bad bot blocking.
