README.md gains a "Deployment" section: what the reverse proxy in front
of pixa must do (terminate TLS, pass Host, Origin and Referer on
unchanged, set X-Forwarded-For with trusted_proxies to match, wait at
least downstream_timeout, optionally refuse /metrics) and what pixa does
itself; that the state directory needs a persistent volume, what
cache_max_bytes counts and why to set it; the health check for a load
balancer; what SIGTERM does and the exit codes; and what running outside
Docker needs. configs/Caddyfile is the example, as Caddy needs no
settings beyond the host name and pixa's address.
Model: opus-5-5
