docs: add logo to all README files

Add centered hero.svg logo above H1 title in all 4 language READMEs
(zh/en/ja/zh-TW). Uses .github/assets/hero.svg at 120px width.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: zhonghui

README.en.md

@@ -17,6 +17,10 @@
 [![Docs](https://img.shields.io/badge/Docs-lordmos.github.io-4a9eff?style=flat-square&logo=vitepress&logoColor=white)](https://lordmos.github.io/tech-editorial/)
 [![Powered by Meridian](https://img.shields.io/badge/Powered%20by-Meridian-f97316?style=flat-square)](https://github.com/lordmos/meridian)
 
+<p align="center">
+  <img src=".github/assets/hero.svg" alt="Scriptorium" width="120"/>
+</p>
+
 # 📚 Scriptorium — Multi-Agent Editorial Framework for Technical Books
 
 > **A multi-agent collaborative writing framework for the "Source Code Reading" series of technical books**

README.ja.md

@@ -19,6 +19,10 @@
 [![Docs](https://img.shields.io/badge/ドキュメント-lordmos.github.io-4a9eff?style=flat-square&logo=vitepress&logoColor=white)](https://lordmos.github.io/tech-editorial/ja/)
 [![Powered by Meridian](https://img.shields.io/badge/Powered%20by-Meridian-f97316?style=flat-square)](https://github.com/lordmos/meridian)
 
+<p align="center">
+  <img src=".github/assets/hero.svg" alt="Scriptorium" width="120"/>
+</p>
+
 # 📚 Scriptorium — 技術書籍マルチエージェント編集部フレームワーク
 
 > **「ソースコード読解シリーズ」技術書籍のマルチエージェント協調執筆フレームワーク**

README.md

@@ -9,6 +9,10 @@
 [![Docs](https://img.shields.io/badge/文档站-在线阅读-4a9eff?style=flat-square&logo=vitepress&logoColor=white)](https://lordmos.github.io/tech-editorial/)
 [![Powered by Meridian](https://img.shields.io/badge/Powered%20by-Meridian-f97316?style=flat-square)](https://github.com/lordmos/meridian)
 
+<p align="center">
+  <img src=".github/assets/hero.svg" alt="Scriptorium" width="120"/>
+</p>
+
 # 📚 Scriptorium — 技术书籍多Agent编辑部框架
 
 > **"源码阅读系列"技术书籍的多Agent协作编写框架**

README.zh-TW.md

@@ -19,6 +19,10 @@
 [![Docs](https://img.shields.io/badge/文件站-在線閱讀-4a9eff?style=flat-square&logo=vitepress&logoColor=white)](https://lordmos.github.io/tech-editorial/zh-TW/)
 [![Powered by Meridian](https://img.shields.io/badge/Powered%20by-Meridian-f97316?style=flat-square)](https://github.com/lordmos/meridian)
 
+<p align="center">
+  <img src=".github/assets/hero.svg" alt="Scriptorium" width="120"/>
+</p>
+
 # 📚 Scriptorium — 技術書籍多Agent編輯部框架
 
 > **"源碼閱讀系列"技術書籍的多Agent協作編寫框架**