The root (main)/layout renders <html> ABOVE the [locale] segment, so next-intl's
getLocale() returns the default locale there - emitting <html lang="en"> on every
page regardless of UI language (e.g. /de) and a hardcoded English <head>
description. Both are strong "translate this page" triggers in Chrome.
proxy.ts already exposes the nonce to server components via the
x-middleware-request-* mechanism; expose the request pathname the same way as
x-pathname, and have the root layout derive the locale from it (falling back to
getLocale() when the path has no locale segment) for both <html lang> and the
localized meta_description (new key in all 17 locales; the English value is
unchanged).