Flip overlays in Linux (yes hacky but works)

src/Ryujinx.Graphics.Gpu/Window.cs

@@ -314,6 +314,14 @@ namespace Ryujinx.Graphics.Gpu
                 // Create canvas for drawing overlays
                 using var canvas = new SKCanvas(bitmap);
                 
+                // On Linux with OpenGL, we need to flip the Y-axis because OpenGL uses bottom-left origin
+                // while SkiaSharp uses top-left origin
+                if (OperatingSystem.IsLinux())
+                {
+                    canvas.Scale(1, -1);
+                    canvas.Translate(0, -height);
+                }
+                
                 // Render all overlays
                 _overlayManager.Render(canvas);