update readme

readme.md

@@ -2,6 +2,15 @@ __English__ · [简体中文](readme_zh.md)
 
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+**[project documentation](https://cdhigh.github.io/KindleEar)**     
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+[Demo Site](https://kindleear.onrender.com/)  
+Note: The demo site is a free service hosted on Render. It may take around 50 seconds to start up the first time you open it. The login credentials are `admin/admin`. All data will be automatically cleared after a period of inactivity, so feel free to perform any operations. You can use it to test ebook pushing.        
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 # Announcement
 June 1, 2024  **Release of KindleEar 3.1, includes an online reader optimized for e-ink (Docker only).**  
 
@@ -36,9 +45,6 @@ Support online reading too, including an online reader specifically optimized fo
 
 
 
-For other details, please refer to the **[project documentation](https://cdhigh.github.io/KindleEar)**.
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-
 
 
 ![Screenshot](https://raw.githubusercontent.com/cdhigh/KindleEar/master/docs/images/scrshot.gif)

readme_zh.md

@@ -2,6 +2,14 @@
 
 ---
 
+**[项目文档](https://cdhigh.github.io/KindleEar)**    
+
+
+[体验站点](https://kindleear.onrender.com/)    
+注：体验站点是在render上搭建的免费服务，第一次打开会大约有50s的启动时间，登录账号密码为 `admin/admin`，一段时间不活动后所有数据会被自动清除，所以可以大胆放心的进行任何操作，你可以进行电子书推送测试。  
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 2024-06-01  **KindleEar 3.1 版本发布，新增一个为墨水屏特别优化的在线阅读器(仅Docker版本)**     
 
 **主要新特性:**
@@ -35,8 +43,6 @@
 * 和Evernote/Pocket/Instapaper/wallabag等系统的集成
 
 
-其他细节请参考 **[项目文档](https://cdhigh.github.io/KindleEar)**
-