Promote lib/host into the docker stack behind blog.rose-ash.com (reusing a
down Quart subdomain). New compose service sx_host runs lib/host/serve.sh on
externalnet; Caddy reverse-proxies blog.rose-ash.com -> sx-dev-sx_host-1:8000.
hosts/ fix: http-listen bound inet_addr_loopback only, unreachable from other
containers. Add SX_HTTP_HOST env (default loopback for tests/local; stack sets
0.0.0.0) in sx_server.ml. serve.sh made container-friendly (SX_PROJECT_DIR).
Verified live through Cloudflare->Caddy: /health, /feed, relations reads serve
real JSON; / 404 (no root route yet). rose-ash.com untouched. Conformance
145/145 green with the rebuilt binary.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>