v0.3.0

When host-scoped routing is configured, requests must arrive under the hostname matching their visibility. A co-located caller (e.g. an SSR frontend on the same host) that hits the server directly on localhost sends Host: localhost, matches no visibility subrouter, and gets a 404.

TrustLoopback opts into additionally registering every route on a shared subrouter that matches a loopback Host (localhost/127.0.0.1/::1, with or without a port). External, per-visibility host matching is unchanged.

Opt-in and fail-closed: only safe when the HTTP port is firewalled to loopback, so the default leaves host gating fully intact.