fix(live): 调整直播退出流程和RTC token续期逻辑

- 修改直播退出时overlay隐藏与页面返回的顺序
- 新增RTC token即将过期时的自动续期处理
- 引入agora_token_generator库以支持token生成
- 在onTokenPrivilegeWillExpire回调中实现token更新机制

lib/rtc/rtc_manager.dart

@@ -1,6 +1,7 @@
 import 'dart:convert';
 
 import 'package:agora_rtc_engine/agora_rtc_engine.dart';
+import 'package:agora_token_generator/agora_token_generator.dart';
 import 'package:dating_touchme_app/rtc/rtm_manager.dart';
 import 'package:flutter/foundation.dart';
 import 'package:get/get.dart';
@@ -260,6 +261,16 @@ class RTCManager {
             onConnectionLost!(connection);
           }
         },
+        onTokenPrivilegeWillExpire: (RtcConnection connection, String token) {
+          String rtcToken = RtcTokenBuilder.buildTokenWithUid(
+            appId: '4c2ea9dcb4c5440593a418df0fdd512d',
+            appCertificate: '16f34b45181a4fae8acdb1a28762fcfa',
+            channelName: _currentChannelId ?? '',
+            uid: _currentUid ?? 0,
+            tokenExpireSeconds: 3600, // 2 hours
+          );
+          _engine?.renewToken(rtcToken);
+        },
         onError: (ErrorCodeType err, String msg) {
           print('RTC Engine 错误：$err，消息：$msg');
           if (onError != null) {

lib/widget/live/live_room_user_header.dart

@@ -138,14 +138,11 @@ class LiveRoomUserHeader extends StatelessWidget {
                             if (hasGuests) SizedBox(height: 15.w),
                             GestureDetector(
                               onTap: () async {
-                                // 关闭弹窗
                                 SmartDialog.dismiss();
-                                // 隐藏 overlay
-                                overlayController.hide();
-                                // 返回上一页
                                 Get.back();
-                                // 调用结束直播方法
+                                overlayController.hide();
                                 await roomController.leaveChannel();
+                                // 隐藏 overlay
                               },
                               child: Row(
                                 mainAxisAlignment: MainAxisAlignment.center,