With the SEO backend unreachable since start, /robots.txt and /sitemap.xml
answered 503 where v0.1.1 left them to the app (a consumer's smoke expects
the app's 404). The root proxies now need a site answer; the last one seen
is kept while the backend is down, so a failure after it is still 503.
- options (cms alias of public.seo.enabled, breadcrumbs, links.newTabHint,
rootFiles, resolveFiles), the new runtime keys and the moved purge keys
- the resolve and site answer contract, one JSON-LD graph, root files,
the purge route, 404 report, labels and tokens, the smoke runs
