Adds a `GATEWAY_PUBLIC_HTTP_CORS_ALLOWED_ORIGINS` env-driven allow-list
on the public REST server so the dev UI on https://www.galaxy.lan can
call https://api.galaxy.lan without the browser blocking the
cross-origin response. Defaults to empty (no CORS) so the production
posture stays closed.
The middleware mounts before route classification and anti-abuse, so
OPTIONS preflights never charge against per-class rate-limit buckets.
`tools/dev-deploy/docker-compose.yml` opts the dev gateway into a
single allowed origin (`https://www.galaxy.lan`); local-dev keeps the
defaults because Vite proxies through the same origin.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>