DomainScope middleware checks Host header per-request — Octane-safe.
Applied to Api homepage (scoped to api.lthn.io). Explorer and Docs
subdomain routes stay disabled — catch-all routes like /{section}/{page?}
match before middleware runs, breaking other routes. These modules
need own containers for proper domain isolation.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
