feat(mobile,deploy): 接入安卓极光与华为通道并准备公网部署配置

客户端默认指向 jxd.jinniu.ink 的 HTTPS/WSS；登录后把 OpenIM userID 设为极光 alias。
华为 agconnect-services.json 不伪造、不入库。Master Secret 只从服务器文件注入。

Co-authored-by: multica-agent <github@multica.ai>

mobile/lib/screens/mine_screen.dart

@@ -2,6 +2,7 @@ import 'package:flutter/material.dart';
 import 'package:flutter_openim_sdk/flutter_openim_sdk.dart';
 
 import '../services/im_service.dart';
+import '../services/push_service.dart';
 import '../theme.dart';
 import '../widgets/avatar.dart';
 import 'login_screen.dart';
@@ -166,6 +167,7 @@ class _MineScreenState extends State<MineScreen> {
             onPressed: () async {
               Navigator.of(ctx).pop();
               await LoginScreen.clearCredential();
+              await PushService.instance.unbindUser();
               await IMService.instance.logout();
               if (!mounted) return;
               Navigator.of(context).pushAndRemoveUntil(