fix: 清理AI遗留代码，修复场景配置

- 删除三套旧菜单系统 (MainMenu.cs, MainMenuUI.cs, ModeSelectionUI.cs)
- Ground 添加 BoxCollider 并设置 tag 为 Ground
- UIManager.OnReturnClicked 改为通过 PageController 返回首页
- PageController 增加 ReturnToHome 方法，管理 BtnFixationBack 可见性
- 清理废弃场景 Experiment.unity / ModeSelection.unity 及历史截图

Doc/WebGLBuildSever/node_modules/call-bound/index.js

@@ -0,0 +1,19 @@
+'use strict';
+
+var GetIntrinsic = require('get-intrinsic');
+
+var callBindBasic = require('call-bind-apply-helpers');
+
+/** @type {(thisArg: string, searchString: string, position?: number) => number} */
+var $indexOf = callBindBasic([GetIntrinsic('%String.prototype.indexOf%')]);
+
+/** @type {import('.')} */
+module.exports = function callBoundIntrinsic(name, allowMissing) {
+	/* eslint no-extra-parens: 0 */
+
+	var intrinsic = /** @type {(this: unknown, ...args: unknown[]) => unknown} */ (GetIntrinsic(name, !!allowMissing));
+	if (typeof intrinsic === 'function' && $indexOf(name, '.prototype.') > -1) {
+		return callBindBasic(/** @type {const} */ ([intrinsic]));
+	}
+	return intrinsic;
+};