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>

internal/ui/app.go

@@ -32,9 +32,10 @@ type view struct {
 
 // App is the top-level arr-tui application.
 type App struct {
-	app   *tview.Application
-	theme theme         // the colors in use
-	trakt *trakt.Client // trending, most watched and anticipated lists
+	app    *tview.Application
+	theme  theme         // the colors in use
+	trakt  *trakt.Client // trending, most watched and anticipated lists, casts
+	people *peopleCache  // casts loaded from Trakt
 	// The Movies and Series views, to refresh their Trakt lists.
 	searches []*searchView
 	themed   *themedScreen // draws with them; nil until Run
@@ -175,6 +176,7 @@ func New(cfg *config.Config) *App {
 		time.Duration(cfg.UI.RefreshSeconds)*time.Second)
 	a.downloads = downloads
 	a.trakt = trakt.NewClient(cfg.Trakt.ClientID, "arr-tui")
+	a.people = newPeopleCache()
 	if u := os.Getenv("ARR_TUI_TRAKT_URL"); u != "" {
 		a.trakt.SetBaseURL(u) // another Trakt API, for development (dev/screenshots)
 	}