项目 5 补齐：旧版线程 API（Suspend / Resume / Abort）与 ListBox

- 编译时把 Thread 的 Suspend / Resume / Abort、ThreadState、Sleep、new Thread 改写成平台的
  协作式实现：被挂起或终止的线程在 Sleep、后台改控件、调设备类库、弹提示框时停下或结束；
  ThreadStateException 等行为与 .NET Framework 一致；编辑器不再提示"已过时"
- ListBox：列表项、单选、SelectedIndexChanged 先于 Click、删除选中项后取消选中；
  ComboBox 与 ListBox 共用 ListControl 和列表项集合；设计器工具箱加"列表框"
- 评分规则的"包含"对列表框检查所有列表项
- 示例：项目 5 任务 2（烟雾，线程）、任务 3（推送灾情，二维数组、两个窗体、ListBox），
  参考答案修正书上直接 Abort 挂起线程、烟雾记成"发现火情"的问题
- 一直不换行的 Console 输出攒满 4096 字符先发出，避免占满内存
- 测试：旧版线程 API、ListBox 事件顺序、两个示例的端到端和评分测试

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/Sim.WinForms/Host/SimHost.cs

@@ -77,13 +77,17 @@ public static class SimHost
 
     public static void SendConsole(string text) => Send(new JsonObject { ["type"] = "console", ["text"] = text });
 
-    public static void SendDevice(string device, string action, object? data) => Send(new JsonObject
+    public static void SendDevice(string device, string action, object? data)
     {
-        ["type"] = "device",
-        ["device"] = device,
-        ["action"] = action,
-        ["data"] = PropValue.From(data),
-    });
+        LegacyThreads.CheckPoint();
+        Send(new JsonObject
+        {
+            ["type"] = "device",
+            ["device"] = device,
+            ["action"] = action,
+            ["data"] = PropValue.From(data),
+        });
+    }
 
     // ---------- 异常 ----------
 
@@ -121,6 +125,7 @@ public static class SimHost
     /// </summary>
     public static JsonNode? Request(JsonObject message)
     {
+        LegacyThreads.CheckPoint();
         var id = Interlocked.Increment(ref _nextRequestId);
         var pending = new PendingRequest();
         Requests[id] = pending;