docs: add logo to README files

Author: pallyoung

README.md

@@ -1,5 +1,11 @@
+<div align="center">
+
+<img src="docs/assets/logo.png" alt="Coder Studio Logo" width="128" height="128">
+
 # Coder Studio
 
+</div>
+
 <div align="center">
 
 **AI Coding Workspace · Browser-Based · Cross-Device · Self-Hosted**

README.zh-CN.md

@@ -1,5 +1,11 @@
+<div align="center">
+
+<img src="docs/assets/logo.png" alt="Coder Studio Logo" width="128" height="128">
+
 # Coder Studio
 
+</div>
+
 <div align="center">
 
 **AI 编程工作台 · 浏览器访问 · 跨设备协作 · 本地运行**