test: replace fixed waits with observable GUI readiness

Advance integration drivers only after their requested controls, game state or file effects are observable. Preserve the behavioral assertions and shared viewport capture pipeline.

test_suites/menu_flow/src/MenuFlowTestDriverNode.cs

@@ -26,6 +26,9 @@ namespace Mods.MenuFlowTest
     /// </summary>
     public partial class MenuFlowTestDriverNode : Node
     {
+        private int readinessToken = int.MinValue;
+        private ulong readinessStarted;
+        private ulong readinessFrame;
         private const string GameId = "novel_template";
         private const string Slot = "slot_942";
         private const string DeletableId = "menu_flow_deletable";
@@ -35,13 +38,13 @@ namespace Mods.MenuFlowTest
         private int passed;
         private int step;
         private double elapsed;
-        private double stepAt;
         private bool done;
         private Node hub;
         private string initialLocale;
         private int languageIndex;
         private bool languageReady;
 
+        /// <summary>Advances when observable scene/UI readiness has held for two real frames; the watchdog remains active.</summary>
         public override void _Process(double delta)
         {
             if (done)
@@ -55,9 +58,6 @@ namespace Mods.MenuFlowTest
                 return;
             }
 
-            if (elapsed - stepAt < 0.5)
-                return;
-            stepAt = elapsed;
 
             try
             {
@@ -72,8 +72,26 @@ namespace Mods.MenuFlowTest
 
         private Control Menu => GetTree().CurrentScene as Control;
 
+        // Deferred UI/scene work must finish before the original assertions run.
+        private bool WaitForReadyFrames(int token, bool ready, double timeoutSeconds = 30)
+        {
+            var now = global::Godot.Time.GetTicksMsec();
+            if (readinessToken != token)
+            {
+                readinessToken = token;
+                readinessStarted = now;
+                readinessFrame = 0;
+            }
+            if (now - readinessStarted > timeoutSeconds * 1000)
+                throw new global::System.TimeoutException($"readiness at step {token}: scene/UI did not become ready");
+            if (!ready) { readinessFrame = 0; return false; }
+            if (readinessFrame == 0) readinessFrame = global::Godot.Engine.GetProcessFrames();
+            return global::Godot.Engine.GetProcessFrames() - readinessFrame >= 2;
+        }
+
         private void RunStep()
         {
+            if (!WaitForReadyFrames(step * 100 + languageIndex * 2 + (languageReady ? 1 : 0), Boot.IsReady && Menu != null && !Cthangover.Core.Scenes.GodotSceneService.IsTransitioning, 30)) return;
             switch (step)
             {
                 case 0: