docs: update WeChat assistant QR code

Author: TATP-233

README.md

@@ -171,10 +171,11 @@ Use the published [UniLab documentation](https://unilabsim.github.io/UniLab-doc/
 
 Join our [Discord server](https://discord.gg/EPCuguRmGX) to chat with the community and get help.
 
-| WeChat Group | Author WeChat |
-| :---: | :---: |
-| <img src="docs/sphinx/source/_static/assets/unilab-wechat-group.jpg" alt="UniLab WeChat group QR code" width="220"> | <img src="docs/sphinx/source/_static/assets/unilab-wechat-assistant.jpg" alt="UniLab author WeChat QR code" width="150"> |
-| Scan to join the UniLab WeChat group. | If the group is full, add the author and include `unilab交流` in your message. |
+<p align="center">
+  <img src="docs/sphinx/source/_static/assets/unilab-wechat-assistant.jpg" alt="UniLab WeChat assistant QR code" width="180">
+</p>
+
+<p align="center">Add the assistant on WeChat to join the group. Please include <code>UniLab community</code> in your request.</p>
 
 ## ⭐ Star History
 

README_zh.md

@@ -173,10 +173,11 @@ uv run eval --algo ppo --task go2_arm_manip_loco --sim motrix --load-run -1
 
 海外用户可加入我们的 [Discord 服务器](https://discord.gg/EPCuguRmGX) 交流与获取帮助。
 
-| 微信群 | 作者微信 |
-| :---: | :---: |
-| <img src="docs/sphinx/source/_static/assets/unilab-wechat-group.jpg" alt="UniLab 微信群二维码" width="220"> | <img src="docs/sphinx/source/_static/assets/unilab-wechat-assistant.jpg" alt="UniLab 作者微信二维码" width="150"> |
-| 扫码加入 UniLab 微信群。 | 如果微信群已满，请添加作者微信，并备注`unilab交流`。 |
+<p align="center">
+  <img src="docs/sphinx/source/_static/assets/unilab-wechat-assistant.jpg" alt="UniLab 小助手微信二维码" width="180">
+</p>
+
+<p align="center">添加小助手微信进群，请备注：<code>unilab交流</code></p>
 
 ## ⭐ Star 趋势