Extended the ZStack overlay fix to all iOS navigation header menus
where text labels would disappear when tapping the menu:
- HomeView: "Home" title menu
- PopularView: "Popular" title with icon menu
- TrendingView: Country/flag title menu
- PlaylistsView: Playlist title with thumbnail menu
- ChannelPlaylistView: Playlist title with thumbnail menu
- OpenVideosView: Playback mode picker menu
All menus now use the same pattern as PlaybackSettings:
- Visible static label layer in ZStack
- Invisible Menu overlay with .opacity(0)
- Prevents text disappearing and resizing animations