fix(plex): the player's ⋯ and tracks lists are real menus, and every close returns the focus

They were hand-built divs: no menu roles, no arrow keys, and Escape left the
focus on <body>. Both run on the popover engine now (media-tone rows), and the
tuning panel is a labelled dialog that takes the focus and hands it back to ⋯.

frontend/src/components/ui/pressableSelectable.contract.test.ts

@@ -27,7 +27,6 @@ const PLAIN: Record<string, [number, string]> = {
   "PlaylistsRail.tsx": [1, "the load-error retry"],
   "PlexCollectionEditor.tsx": [1, "a checkbox row in a picker"],
   "PlexInfo.tsx": [1, "the rating filter (a number)"],
-  "PlexPlayer.tsx": [4, "track picker rows and the ⋯ menu's rows"],
   "PlexPlayerSettings.tsx": [2, "setting options"],
   "PlexPlaylistAdd.tsx": [1, "a checkbox row in a picker"],
   "PlexPlaylistView.tsx": [1, "a show's poster stack (aria-hidden)"],