feat: 添加微信SDK和关卡页面，重构预制体结构

- 新增 WxSDK 微信SDK工具类
- 新增 PageLevel 关卡选择页面组件
- 将 prefabs 目录从 resources 移至根目录
- 更新 ViewManager 支持预制体属性引用
- 添加 BaseView 页面基类

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

assets/main.scene

@@ -399,6 +399,14 @@
     },
     "_enabled": true,
     "__prefab": null,
+    "pageHomePrefab": {
+      "__uuid__": "ae6e1ab4-19be-4cb3-90e4-9a1f3204a0fd",
+      "__expectedType__": "cc.Prefab"
+    },
+    "pageLevelPrefab": {
+      "__uuid__": "8611dbdc-4749-49f1-97ca-aedae3d16320",
+      "__expectedType__": "cc.Prefab"
+    },
     "_id": "c2b3nbzv9JuZmP2jxQyN72"
   },
   {