fix: address code review feedback

- Fix Task.CompletedTask -> UniTask.CompletedTask
- Fix AsUniTask to delegate to awaiter (prevent double pool return)
- Fix Reset to return execution contexts to pool before clearing
- Fix MessageBox test hooks to use direct index access (avoid foreach)
- Add comment explaining PlayerLoop single-threading in parallel test

Signed-off-by: JasonXuDeveloper - 傑 <jason@xgamedev.net>

Author: JasonXuDeveloper

UnityProject/Packages/com.jasonxudeveloper.jengine.ui/Runtime/MessageBox.cs

@@ -143,16 +143,8 @@ internal static bool TestSimulateButtonClick(bool clickOk)
         {
             if (ActiveMessageBoxes.Count == 0) return false;
 
-            // Get the most recent message box (any will do for testing)
-            MessageBox target = null;
-            foreach (var box in ActiveMessageBoxes)
-            {
-                target = box;
-                break;
-            }
-
-            if (target == null) return false;
-
+            // Get the first message box (any will do for testing)
+            var target = ActiveMessageBoxes[0];
             target.HandleEvent(clickOk);
             return true;
         }
@@ -165,14 +157,8 @@ internal static (bool okVisible, bool noVisible)? TestGetButtonVisibility()
         {
             if (ActiveMessageBoxes.Count == 0) return null;
 
-            MessageBox target = null;
-            foreach (var box in ActiveMessageBoxes)
-            {
-                target = box;
-                break;
-            }
-
-            if (target == null || target._buttonOk == null || target._buttonNo == null)
+            var target = ActiveMessageBoxes[0];
+            if (target._buttonOk == null || target._buttonNo == null)
                 return null;
 
             return (target._buttonOk.gameObject.activeSelf, target._buttonNo.gameObject.activeSelf);
@@ -186,15 +172,7 @@ internal static (string title, string content, string okText, string noText)? Te
         {
             if (ActiveMessageBoxes.Count == 0) return null;
 
-            MessageBox target = null;
-            foreach (var box in ActiveMessageBoxes)
-            {
-                target = box;
-                break;
-            }
-
-            if (target == null) return null;
-
+            var target = ActiveMessageBoxes[0];
             return (
                 target._title?.text,
                 target._content?.text,

UnityProject/Packages/com.jasonxudeveloper.jengine.util/Runtime/JAction.cs

@@ -910,8 +910,20 @@ public JAction Reset(bool force = false)
             _onCancelDelegate = null;
             _onCancelState?.Return();
             _onCancelState = null;
+
+            // Return active execution contexts to pool before clearing
+            for (int i = 0; i < _activeContexts.Count; i++)
+            {
+                JActionExecutionContext.Return(_activeContexts[i]);
+            }
             _activeContexts.Clear();
-            _syncContext = null;
+
+            // Return sync execution context to pool
+            if (_syncContext != null)
+            {
+                JActionExecutionContext.Return(_syncContext);
+                _syncContext = null;
+            }
 
             return this;
         }

UnityProject/Packages/com.jasonxudeveloper.jengine.util/Runtime/JActionExecutionHandle.cs

@@ -87,16 +87,9 @@ public void Cancel()
         /// </summary>
         public async UniTask<JActionExecution> AsUniTask()
         {
-            await new JActionAwaitable(_context);
-            _action?.RemoveActiveContext(_context);
-
-            // Capture cancelled state before returning context to pool
-            bool cancelled = _context?.Cancelled ?? false;
-
-            // Return context to pool
-            JActionExecutionContext.Return(_context);
-
-            return new JActionExecution(_action, cancelled);
+            // Delegate to the handle's awaiter so that completion and cleanup
+            // are managed in a single, centralized location.
+            return await this;
         }
 
         /// <summary>

UnityProject/Packages/com.jasonxudeveloper.jengine.util/Tests/Runtime/JActionRuntimeTests.cs

@@ -488,6 +488,9 @@ public IEnumerator Do_AsyncFuncWithState_PassesState()
         [UnityTest]
         public IEnumerator Parallel_AllowsConcurrentExecution()
         {
+            // Note: This test is safe despite shared variables because Unity's PlayerLoop
+            // executes on a single thread. The increment/decrement operations are not
+            // racing with each other - they execute sequentially within the same frame.
             int concurrentCount = 0;
             int maxConcurrent = 0;
 
@@ -580,7 +583,7 @@ public IEnumerator Parallel_Property_ReflectsState()
                 action1.Dispose();
                 action2.Dispose();
 
-                await Task.CompletedTask;
+                await UniTask.CompletedTask;
             });
         }