feat: Implement Playlists and Programs Management

- Added PlaylistsGroupViewModel to manage playlists and selection.
- Introduced ProgramsGroupViewModel for handling program groups and subscriptions.
- Created ProgramsListViewModel to manage individual program listings.
- Developed SettingsViewModel for user settings including playlist management.
- Implemented TVPlayerViewModel as the main view model coordinating screens and data.
- Added PlayerView for video playback with LibVLC integration.
- Created XAML views for PlaylistsGroup, ProgramsGroup, ProgramsList, and Settings.
- Added sample M3U playlist for testing.
- Documented WPF build instructions and project structure in WPF-BUILD.md.
- Configured global.json for .NET SDK versioning.

TV Player Avalonia/ViewModels/PlaylistsGroupViewModel.cs

@@ -0,0 +1,32 @@
+using CommunityToolkit.Mvvm.Input;
+using System.Windows.Input;
+
+namespace TV_Player.AvaloniaApp.ViewModels;
+
+public class PlaylistsGroupViewModel : TV_Player.ObservableViewModelBase
+{
+    private List<GroupInfo> _programs = new();
+    public List<GroupInfo> Programs
+    {
+        get => _programs;
+        set => SetProperty(ref _programs, value);
+    }
+
+    public ICommand SelectPlaylistCommand { get; }
+
+    public PlaylistsGroupViewModel()
+    {
+        SelectPlaylistCommand = new RelayCommand<GroupInfo>(OnItemSelected);
+        Programs = TVPlayerViewModel.Instance.PlayListsData
+            .Select(x => new GroupInfo { Name = x.Key, Count = 0 })
+            .ToList();
+    }
+
+    private void OnItemSelected(GroupInfo? group)
+    {
+        if (group == null)
+            return;
+
+        TVPlayerViewModel.Instance.ShowProgramsGroupScreen(group.Name);
+    }
+}