Details pane: director and cast from Trakt

With a Trakt client ID, the details of a movie or series show the
director(s) or creators and up to 8 cast members with their roles below
the plot, in every view. The title is found on Trakt by its TMDb/TVDB
(else IMDb) id, then its people are read. Casts are cached and, like
posters, only loaded once the selection rests.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

README.md

@@ -12,6 +12,8 @@ A terminal UI to search for movies and series with [Radarr](https://radarr.video
   lists from [Trakt](https://trakt.tv): trending now, most watched this week, anticipated, popular,
   and the US box office for movies. `[` and `]` switch lists; titles already in your library are
   ticked, the others can be added right there (Enter). Needs a free Trakt client ID (see Configure).
+- **Cast**: with a Trakt client ID, the details pane also lists the director (or the creators of a
+  series) and the cast with their roles, below the plot, in every view.
 - **Interactive search**: list the releases Radarr/Sonarr find (approved or rejected, with reasons),
   sort and filter them (by approval, quality, x265 / x264 / AV1, HDR, Dolby Vision, audio format, language), and grab one. Series: pick a season or a single episode first.
 - **Posters**: the detail panes show the poster at the top right; title, facts, path and plot