结构调整，便于后续扩展

AIStudio.Wpf.Flowchart/SelectOption.cs

@@ -0,0 +1,16 @@
+namespace AIStudio.Wpf.Flowchart
+{
+    /// <summary>
+    /// 前端SelectOption
+    /// </summary>
+    public class SelectOption
+    {
+        public string value { get; set; }
+        public string text { get; set; }
+
+        public override string ToString()
+        {
+            return text;
+        }
+    }
+}