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/Program.cs

@@ -0,0 +1,15 @@
+using Avalonia;
+using System;
+
+namespace TV_Player.AvaloniaApp;
+
+internal static class Program
+{
+    [STAThread]
+    public static void Main(string[] args) => BuildAvaloniaApp().StartWithClassicDesktopLifetime(args);
+
+    public static AppBuilder BuildAvaloniaApp()
+        => AppBuilder.Configure<App>()
+            .UsePlatformDetect()
+            .LogToTrace();
+}