Opening a members-only video from a history or feed row got a 500 from
the videos API and left the detail view blank: the retry error view only
covered the videoID init mode, while the details fetch for a loaded
video failed silently.
Record the details-fetch error and route it into the same error view
when the displayed video is a bare placeholder (no author, no
thumbnails), show a spinner while that fetch is in flight, and make
retry re-run both loaders. Videos with real partial metadata keep
rendering as before.