Fix: Silently handle InvalidCastException from WPF system resource invalidation on Windows theme change

Co-authored-by: Jack251970 <53996452+Jack251970@users.noreply.github.com>

Flow.Launcher/Helper/ErrorReporting.cs

@@ -25,6 +25,12 @@ public static class ErrorReporting
         // This change modifies the behavior to log the exception instead of showing the "Error report UI".
         if (ExceptionHelper.IsRecoverableDwmCompositionException(e)) return;
 
+        // Workaround for a WPF issue where changing the Windows theme or accent color triggers
+        // SystemResources.InvalidateTreeResources, which tries to clone Color values stored in styles
+        // and fails with an InvalidCastException. This is a benign framework-level exception that
+        // does not affect Flow Launcher functionality, so we log it silently instead of showing the error dialog.
+        if (ExceptionHelper.IsRecoverableSystemResourceException(e)) return;
+
         var reportWindow = new ReportWindow(e);
         reportWindow.Show();
     }

Flow.Launcher/Helper/ExceptionHelper.cs

@@ -39,4 +39,23 @@ internal static class ExceptionHelper
         return !string.IsNullOrEmpty(stackTrace) &&
                stackTrace.Contains("DwmCompositionChanged", StringComparison.OrdinalIgnoreCase);
     }
+
+    /// <summary>
+    /// Returns true if the exception is a recoverable WPF system resource invalidation exception
+    /// that occurs when Windows changes its theme or accent colors. This is a known WPF issue where
+    /// <c>Color</c> values stored in styles are incorrectly cloned during resource tree invalidation.
+    /// </summary>
+    internal static bool IsRecoverableSystemResourceException(Exception exception)
+    {
+        if (exception is not InvalidCastException)
+        {
+            return false;
+        }
+
+        // Check for the specific Color-to-Expression cast failure originating from WPF's
+        // SystemResources.InvalidateTreeResources, triggered by Windows theme/accent color changes.
+        var stackTrace = exception.StackTrace;
+        return !string.IsNullOrEmpty(stackTrace) &&
+               stackTrace.Contains("System.Windows.SystemResources.InvalidateTreeResources", StringComparison.Ordinal);
+    }
 }