add demo video to README files

README.md

@@ -47,6 +47,12 @@ Moving beyond traditional human-in-the-loop systems, EvoScientist adopts a human
 <!-- <a href="https://github.com/EvoScientist/EvoScientist">
 <img width="100%" src="https://github.com/EvoScientist/EvoScientist/tree/main/.github/assets/EvoScientist_demo.gif?raw=true"></a> -->
 
+<div align="center">
+  <video src="https://github.com/user-attachments/assets/a40ba429-bb07-4663-b5b1-77aed1a833b9" autoplay loop muted playsinline width="80%">
+    <a href="https://github.com/user-attachments/assets/a40ba429-bb07-4663-b5b1-77aed1a833b9">View demo video</a>
+  </video>
+</div>
+
 ## ✨ Features
 - **🤖 Multi-Agent Team** — 6 sub-agents (plan, research, code, debug, analyze, write) working in concert.
 - **🧠 Persistent Memory** — Context, preferences, and findings survive across sessions.

README.zh-CN.md

@@ -54,6 +54,12 @@ EvoScientist 超越了传统的人在回路（Human-in-the-Loop）模式，采
 <!-- <a href="https://github.com/EvoScientist/EvoScientist">
 <img width="100%" src="https://github.com/EvoScientist/EvoScientist/tree/main/.github/assets/EvoScientist_demo.gif?raw=true"></a> -->
 
+<div align="center">
+  <video src="https://github.com/user-attachments/assets/a40ba429-bb07-4663-b5b1-77aed1a833b9" autoplay loop muted playsinline width="80%">
+    <a href="https://github.com/user-attachments/assets/a40ba429-bb07-4663-b5b1-77aed1a833b9">观看演示视频</a>
+  </video>
+</div>
+
 ## ✨ 特性
 
 - **🤖 多智能体协作** — 6 个子智能体（规划、调研、编码、调试、分析、写作）协同工作。