Replace app icon with LlamaCasty brand figure

- Assets/llamacasty-icon.png: new brand llama figure (no text)
- Assets/llamacasty-icon.ico: converted from PNG for executable
- Assets/llamacasty-logo.jpg: full logo with text
- ytLive.csproj: updated ApplicationIcon and Resource references
- All XAML windows: updated Icon references to new file

MainWindow.xaml

@@ -9,7 +9,7 @@
         mc:Ignorable="d"
         Title="{Binding WindowTitle}" Height="720" Width="1280"
         MinWidth="1180" MinHeight="600"
-        Icon="/ytLive;component/Assets/tyllive-icon.png"
+        Icon="/ytLive;component/Assets/llamacasty-icon.png"
         Background="#1a1a2e"
         WindowStartupLocation="CenterScreen"
         Closing="MainWindow_Closing"