Back color configurable, added fps counter checkbox

Editor/Core/SplashControlPanel.cs

@@ -594,6 +594,10 @@ namespace SplashEdit.EditorCode
                 new GUIContent("Memory Overlay", "Show heap/RAM usage bar at top-right during gameplay"),
                 SplashSettings.MemoryOverlay);
 
+            SplashSettings.FpsOverlay = EditorGUILayout.Toggle(
+                new GUIContent("FPS Overlay", "Show an FPS counter at top-left during gameplay"),
+                SplashSettings.FpsOverlay);
+
             // Serial port (only for Real Hardware)
             if (SplashSettings.Target == BuildTarget.RealHardware)
             {
@@ -1187,6 +1191,9 @@ namespace SplashEdit.EditorCode
 
             if (SplashSettings.MemoryOverlay)
                 buildArg += " MEMOVERLAY=1";
+            
+            if (SplashSettings.FpsOverlay)
+                buildArg += " FPSOVERLAY=1";
 
             int jobCount = Math.Max(1, SystemInfo.processorCount - 1);
             string cleanPrefix = SplashSettings.CleanBuild ? "make clean && " : "";