docs: embed README hero image

Author: ymkiux

README.md

@@ -17,7 +17,7 @@
 [Docs](https://sakurabytecore.github.io/codexmate/) · [Quick Start](#quick-start) · [Commands](#command-reference) · [Web UI](#web-ui) · [MCP](#mcp) · [中文](README.zh.md)
 
 <br />
-<a href="https://ibb.co/CKffDS2K"><img src="https://i.ibb.co/5hPPwJFh/3993b7910fc1001e102dd0f9a8673db7.png" alt="Codex Mate screenshot" width="960" /></a>
+<img src="site/.vitepress/public/images/readme-hero.png" alt="Codex Mate screenshot" width="960" />
 
 </div>
 

README.zh.md

@@ -17,7 +17,7 @@
 [文档](https://sakurabytecore.github.io/codexmate/) · [快速开始](#快速开始) · [命令速查](#命令速查) · [Web 界面](#web-界面) · [MCP](#mcp) · [English](README.md)
 
 <br />
-<a href="https://ibb.co/CKffDS2K"><img src="https://i.ibb.co/5hPPwJFh/3993b7910fc1001e102dd0f9a8673db7.png" alt="Codex Mate 界面预览" width="960" /></a>
+<img src="site/.vitepress/public/images/readme-hero.png" alt="Codex Mate 界面预览" width="960" />
 
 </div>