feat(ui): route locked tiers through About

Keep non-owner resolution choices visible but muted. Selecting one preserves the free tier and opens About; external navigation is only the explicit llamacasty.com link. Ref: https://streamlabs.com/desktop

ViewModels/MainViewModel.cs

@@ -199,7 +199,7 @@ public partial class MainViewModel : ViewModelBase
         _youtubeChat = new YouTubeChatService(_youtubeAuth);
         AppLog.Write("MainViewModel ctor: services created");
 
-        _selectedQuality = QualityOptions[0];
+        _selectedQuality = OutputProfile.Resolve(QualityOptions[0], QualityOptions, HasProOutput);
         ApplyStreamQuality(_selectedQuality);
 
         _youtubeChat.MessageReceived += OnChatMessageReceived;
@@ -274,7 +274,7 @@ public partial class MainViewModel : ViewModelBase
         TestAlertCommand = new RelayCommand(_ => TestAlert());
         OpenBugCommand = new RelayCommand(_ => ShowOverlay(nameof(IsBugOpen), "Report Bug"));
         OpenFeatureCommand = new RelayCommand(_ => ShowOverlay(nameof(IsFeatureOpen), "Feature Request"));
-        OpenAboutCommand = new RelayCommand(_ => ShowOverlay(nameof(IsAboutOpen), "About"));
+        OpenAboutCommand = new RelayCommand(_ => ShowAbout());
         CloseOverlayCommand = new RelayCommand(_ => ShowOverlay());
         SubmitBugCommand = new RelayCommand(_ => SubmitBug());
         SubmitFeatureCommand = new RelayCommand(_ => SubmitFeature());