Playable files in the media source browser now honor tvOSVideoTapAction
on tvOS and thumbnailTapAction/textAreaTapAction on iOS/macOS, matching
other video lists. When openInfo navigates to VideoInfoView, playback
routes through QueueManager.playFromMediaBrowser so stream and caption
resolution keep working for Samba/WebDAV files.
On tvOS, ContentUnavailableView inside a Group doesn't expand to fill
available space — it sizes to content and aligns top-leading. Add
.frame(maxWidth: .infinity, maxHeight: .infinity) to all instances
so they center correctly in their parent containers.
