新增 scene.signal 信号交互插件，落地 PLC 握手与扫车放行。

Co-authored-by: Cursor <cursoragent@cursor.com>

StandardScene.Signal/Model/ReleasePointModel.cs

@@ -0,0 +1,14 @@
+using System.ComponentModel;
+
+namespace StandardScene.Signal.Model
+{
+    /// <summary>放行点配置。对应反编译 <c>StartSignModel</c>。</summary>
+    public class ReleasePointModel
+    {
+        [DisplayName("放行站点")]
+        public int Sit { get; set; }
+
+        [DisplayName("启用")]
+        public bool IsUse { get; set; } = true;
+    }
+}