fix(game): 清理 SceneRouterBase 低风险异步包装

- 重构 Replace、Push、Pop、Clear 的 around pipeline 核心委托，移除匿名 async 包装

- 补充 BeforeChange 与 AfterChange 的 ConfigureAwait(false)，收敛明显低风险 MA0004

- 保留场景生命周期与栈操作相关 await 的默认上下文行为，并在代码中说明原因

GFramework.Game/Scene/SceneRouterBase.cs

@@ -89,13 +89,9 @@ public abstract class SceneRouterBase
 
             var @event = CreateEvent(sceneKey, SceneTransitionType.Replace, param);
 
-            await _pipeline.ExecuteAroundAsync(@event, async () =>
+            await _pipeline.ExecuteAroundAsync(
-            {
+                @event,
-                await BeforeChangeAsync(@event);
+                () => ExecuteReplaceCoreAsync(@event, sceneKey, param)).ConfigureAwait(false);
-                await ClearInternalAsync();
-                await PushInternalAsync(sceneKey, param);
-                await AfterChangeAsync(@event);
-            });
         }
         finally
         {
@@ -195,12 +191,9 @@ public abstract class SceneRouterBase
 
             var @event = CreateEvent(sceneKey, SceneTransitionType.Push, param);
 
-            await _pipeline.ExecuteAroundAsync(@event, async () =>
+            await _pipeline.ExecuteAroundAsync(
-            {
+                @event,
-                await BeforeChangeAsync(@event);
+                () => ExecutePushCoreAsync(@event, sceneKey, param)).ConfigureAwait(false);
-                await PushInternalAsync(sceneKey, param);
-                await AfterChangeAsync(@event);
-            });
         }
         finally
         {
@@ -276,12 +269,9 @@ public abstract class SceneRouterBase
 
             var @event = CreateEvent(null, SceneTransitionType.Pop);
 
-            await _pipeline.ExecuteAroundAsync(@event, async () =>
+            await _pipeline.ExecuteAroundAsync(
-            {
+                @event,
-                await BeforeChangeAsync(@event);
+                () => ExecutePopCoreAsync(@event)).ConfigureAwait(false);
-                await PopInternalAsync();
-                await AfterChangeAsync(@event);
-            });
         }
         finally
         {
@@ -347,12 +337,9 @@ public abstract class SceneRouterBase
 
             var @event = CreateEvent(null, SceneTransitionType.Clear);
 
-            await _pipeline.ExecuteAroundAsync(@event, async () =>
+            await _pipeline.ExecuteAroundAsync(
-            {
+                @event,
-                await BeforeChangeAsync(@event);
+                () => ExecuteClearCoreAsync(@event)).ConfigureAwait(false);
-                await ClearInternalAsync();
-                await AfterChangeAsync(@event);
-            });
         }
         finally
         {
@@ -378,6 +365,66 @@ public abstract class SceneRouterBase
 
     #region Helper Methods
 
+    /// <summary>
+    /// 执行 Replace 的核心切换顺序。
+    /// </summary>
+    /// <param name="event">场景转换事件。</param>
+    /// <param name="sceneKey">目标场景键名。</param>
+    /// <param name="param">场景进入参数。</param>
+    /// <returns>异步任务。</returns>
+    private async Task ExecuteReplaceCoreAsync(
+        SceneTransitionEvent @event,
+        string sceneKey,
+        ISceneEnterParam? param)
+    {
+        // 场景生命周期回调可能依赖引擎线程，因此这里保留默认 await 行为。
+        await BeforeChangeAsync(@event);
+        await ClearInternalAsync();
+        await PushInternalAsync(sceneKey, param);
+        await AfterChangeAsync(@event);
+    }
+
+    /// <summary>
+    /// 执行 Push 的核心切换顺序。
+    /// </summary>
+    /// <param name="event">场景转换事件。</param>
+    /// <param name="sceneKey">目标场景键名。</param>
+    /// <param name="param">场景进入参数。</param>
+    /// <returns>异步任务。</returns>
+    private async Task ExecutePushCoreAsync(
+        SceneTransitionEvent @event,
+        string sceneKey,
+        ISceneEnterParam? param)
+    {
+        await BeforeChangeAsync(@event);
+        await PushInternalAsync(sceneKey, param);
+        await AfterChangeAsync(@event);
+    }
+
+    /// <summary>
+    /// 执行 Pop 的核心切换顺序。
+    /// </summary>
+    /// <param name="event">场景转换事件。</param>
+    /// <returns>异步任务。</returns>
+    private async Task ExecutePopCoreAsync(SceneTransitionEvent @event)
+    {
+        await BeforeChangeAsync(@event);
+        await PopInternalAsync();
+        await AfterChangeAsync(@event);
+    }
+
+    /// <summary>
+    /// 执行 Clear 的核心切换顺序。
+    /// </summary>
+    /// <param name="event">场景转换事件。</param>
+    /// <returns>异步任务。</returns>
+    private async Task ExecuteClearCoreAsync(SceneTransitionEvent @event)
+    {
+        await BeforeChangeAsync(@event);
+        await ClearInternalAsync();
+        await AfterChangeAsync(@event);
+    }
+
     /// <summary>
     /// 创建场景转换事件对象。
     /// </summary>
@@ -407,7 +454,7 @@ public abstract class SceneRouterBase
     private async Task BeforeChangeAsync(SceneTransitionEvent @event)
     {
         Log.Debug("BeforeChange phases started: {0}", @event.TransitionType);
-        await _pipeline.ExecuteAsync(@event, SceneTransitionPhases.BeforeChange);
+        await _pipeline.ExecuteAsync(@event, SceneTransitionPhases.BeforeChange).ConfigureAwait(false);
         Log.Debug("BeforeChange phases completed: {0}", @event.TransitionType);
     }
 
@@ -418,7 +465,7 @@ public abstract class SceneRouterBase
     private async Task AfterChangeAsync(SceneTransitionEvent @event)
     {
         Log.Debug("AfterChange phases started: {0}", @event.TransitionType);
-        await _pipeline.ExecuteAsync(@event, SceneTransitionPhases.AfterChange);
+        await _pipeline.ExecuteAsync(@event, SceneTransitionPhases.AfterChange).ConfigureAwait(false);
         Log.Debug("AfterChange phases completed: {0}", @event.TransitionType);
     }