Sveltia/Decap i18n structures (single_file, multiple_files,
multiple_folders) can neither produce <slug>/<locale>.md nor carry a
shared non-localized meta file, so the folder is exposed as three
monolingual entry collections pinned to their file by the path
template: blog -> <slug>/meta.md, blog-fr -> <slug>/fr.md, blog-en ->
<slug>/en.md. app_id and PKCE untouched.