(client) feat:实现摄像机跟踪与移动，实现任意位置生成实体，实现更安全的资源加载方式（指定unity内部加载资源） (#42)

Co-authored-by: zzdxxz <2079238449@qq.com>
Co-committed-by: zzdxxz <2079238449@qq.com>

Client/Assets/Scripts/Data/BehaviorTreeDef.cs

@@ -0,0 +1,40 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Xml.Linq;
+
+namespace Data
+{
+    public class BehaviorTreeDef : Define
+    {
+        public BehaviorTreeDef[] childTree;
+        public string className="Selector";
+        public string value;
+        
+        
+        public override bool Init(XElement xmlDef)
+        {
+            base.Init(xmlDef);
+
+            // 从当前节点获取className和condition属性
+            className = xmlDef.Attribute("className")?.Value ?? className;
+            value = xmlDef.Attribute("value")?.Value;
+
+            var nodes = xmlDef.Elements("Node");
+            if (!nodes.Any())
+                return true; // 没有子节点也是有效的
+            
+            List<BehaviorTreeDef> children = new();
+            foreach (var node in nodes)
+            {
+                var childNode = new BehaviorTreeDef();
+                if (!childNode.Init(node))
+                    return false;
+                children.Add(childNode);
+            }
+
+            childTree = children.ToArray();
+            return true;
+        }
+    }
+
+}