feat(coroutine): 添加协程组合扩展功能并优化节点存活检查

- 为SendCommandCoroutineWithErrorHandler方法的onError参数添加默认值null
- 新增CoroutineComposeExtensions扩展类，提供Then方法实现协程顺序组合
- 优化CancelWith扩展方法，改进节点存活检查逻辑
- 使用LINQ All方法简化节点存活状态检查代码
- 添加完整的XML文档注释支持

GFramework.Core/coroutine/extensions/CommandCoroutineExtensions.cs

@@ -36,7 +36,7 @@ public static class CommandCoroutineExtensions
     public static IEnumerator<IYieldInstruction> SendCommandCoroutineWithErrorHandler<TCommand>(
         this IContextAware contextAware,
         TCommand command,
-        Action<Exception>? onError)
+        Action<Exception>? onError = null)
         where TCommand : class, IAsyncCommand
     {
         var task = contextAware.GetContext().SendCommandAsync(command);

GFramework.Core/coroutine/extensions/CoroutineComposeExtensions.cs

@@ -0,0 +1,59 @@
+// Copyright (c) 2026 GeWuYou
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+// 
+//     http://www.apache.org/licenses/LICENSE-2.0
+// 
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+using GFramework.Core.Abstractions.coroutine;
+
+namespace GFramework.Core.coroutine.extensions;
+
+/// <summary>
+/// 提供协程组合扩展方法的静态类
+/// </summary>
+public static class CoroutineComposeExtensions
+{
+    /// <summary>
+    /// 将一个协程枚举器与一个动作组合，先执行完第一个协程，然后执行指定的动作
+    /// </summary>
+    /// <param name="first">第一个协程枚举器</param>
+    /// <param name="next">在第一个协程完成后要执行的动作</param>
+    /// <returns>组合后的协程枚举器</returns>
+    public static IEnumerator<IYieldInstruction> Then(
+        this IEnumerator<IYieldInstruction> first,
+        Action next)
+    {
+        // 执行第一个协程的所有步骤
+        while (first.MoveNext())
+            yield return first.Current;
+
+        // 第一个协程完成后执行指定动作
+        next();
+    }
+
+    /// <summary>
+    /// 将两个协程枚举器顺序组合，先执行完第一个协程，再执行第二个协程
+    /// </summary>
+    /// <param name="first">第一个协程枚举器</param>
+    /// <param name="second">第二个协程枚举器</param>
+    /// <returns>组合后的协程枚举器</returns>
+    public static IEnumerator<IYieldInstruction> Then(
+        this IEnumerator<IYieldInstruction> first,
+        IEnumerator<IYieldInstruction> second)
+    {
+        // 执行第一个协程的所有步骤
+        while (first.MoveNext())
+            yield return first.Current;
+
+        // 第一个协程完成后执行第二个协程的所有步骤
+        while (second.MoveNext())
+            yield return second.Current;
+    }
+}

GFramework.Godot/coroutine/CoroutineExtensions.cs

@@ -45,20 +45,25 @@ public static class CoroutineExtensions
     /// <summary>
     ///     让协程在多个节点都被销毁时自动取消
     /// </summary>
+    /// <param name="coroutine">要执行的协程枚举器</param>
+    /// <param name="nodes">用于检查是否存活的节点数组</param>
+    /// <returns>包装后的协程枚举器</returns>
     public static IEnumerator<IYieldInstruction> CancelWith(
         this IEnumerator<IYieldInstruction> coroutine,
         params Node[] nodes)
     {
+        // 持续执行协程直到任一节点被销毁或协程执行完毕
         while (AllNodesAlive(nodes) && coroutine.MoveNext())
             yield return coroutine.Current;
     }
 
+    /// <summary>
+    ///     检查所有节点是否都处于存活状态
+    /// </summary>
+    /// <param name="nodes">要检查的节点数组</param>
+    /// <returns>如果所有节点都存活则返回true，否则返回false</returns>
     private static bool AllNodesAlive(Node[] nodes)
     {
-        foreach (var node in nodes)
-            if (!Timing.IsNodeAlive(node))
-                return false;
-
-        return true;
+        return nodes.All(Timing.IsNodeAlive);
     }
 }