CVE-2026-113668: ApostropheCMS: :_id/locales REST route omits the public-API authorization gate its sibling read routes enforce (unauthenticated doc-existence + locale metadata disclosure)

The REST route GET /api/v1/<piece-type>/:_id/locales (and the equivalent page route) does not apply the publicApiCheckAsync gate that ApostropheCMS’s other read routes enforce. An unauthenticated caller can therefore query this route for any document _id and learn whether the document exists and which locales it is published in — a document-existence and locale-metadata disclosure that the read-API is otherwise supposed to gate.