Fix: guard editor-only gaze evaluation call for player builds

ScheduleEditorFinalEvaluation is defined under UNITY_EDITOR but was
called unguarded in ProcessFrame, breaking player builds with CS0103.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

Runtime/Gaze/Timeline/BlendshapeGazeMixerBehaviour.cs

@@ -169,6 +169,7 @@ namespace Streamingle.Gaze
             hasSubmittedState = true;
             hasProcessedFrame = true;
 
+#if UNITY_EDITOR
             if (!Application.isPlaying)
             {
                 // Evaluate after the whole Timeline graph has applied its animation
@@ -176,6 +177,7 @@ namespace Streamingle.Gaze
                 // and facial blendshape baseline from this frame.
                 ScheduleEditorFinalEvaluation(driver);
             }
+#endif
         }
 
         public override void OnGraphStop(Playable playable)