react19废弃的render方法

**Version information (版本信息)**
- ChatUI or ChatUI Pro? ChatUI
- ChatUI Version: 3.0.0
- React Version: 19.1.0
- OS Version: mac os 15.4.1
- Browser Version: Chromium 136

**Describe the bug (描述问题)**
react19已完全废弃了react-dom的render方法，而ChatUI代码中看起来仅src/utils/mountComponent.ts:19这一处使用了废弃的render方法，导致toast等功能无法使用。

**Expected behavior (期望的结果是什么)**
希望尽快发布补丁版本。

Start with src/utils/mountComponent.ts:19 and inspect how the deprecated react-dom render method is used. Reproduce the issue with React 19.1.0, then verify that toast and related functionality works with the supported mounting approach.

Written by the indexing model from the issue text.