docs: simplify navigation by removing redundant English documentation links

- Remove English documentation from sidebar navigation
- Remove language selection from main index page
- Keep only Chinese documentation in the main navigation
- English documentation remains available but not prominently displayed

Author: loveTsong

_includes/sidebar.html

@@ -3,7 +3,7 @@ <h3>目录</h3>
   <ul>
     <li><a href="{{ '/' | relative_url }}">首页</a></li>
     <li>
-      <a href="{{ '/docs/zh_CN/' | relative_url }}">中文文档</a>
+      <a href="{{ '/docs/zh_CN/' | relative_url }}">文档</a>
       <ul>
         <li><a href="{{ '/docs/zh_CN/model-access/' | relative_url }}">模型接入</a></li>
         <li><a href="{{ '/docs/zh_CN/build-agent/' | relative_url }}">构建智能体</a></li>
@@ -15,19 +15,6 @@ <h3>目录</h3>
         <li><a href="{{ '/docs/zh_CN/application-market/' | relative_url }}">应用市场</a></li>
       </ul>
     </li>
-    <li>
-      <a href="{{ '/docs/en_US/' | relative_url }}">English Docs</a>
-      <ul>
-        <li><a href="{{ '/docs/en_US/model-access/' | relative_url }}">Model Access</a></li>
-        <li><a href="{{ '/docs/en_US/build-agent/' | relative_url }}">Build Agent</a></li>
-        <li><a href="{{ '/docs/en_US/build-conversational-assistant/' | relative_url }}">Build Conversational Assistant</a></li>
-        <li><a href="{{ '/docs/en_US/workflow/' | relative_url }}">Workflow</a></li>
-        <li><a href="{{ '/docs/en_US/knowledge-base/' | relative_url }}">Knowledge Base</a></li>
-        <li><a href="{{ '/docs/en_US/plugins/' | relative_url }}">Plugin</a></li>
-        <li><a href="{{ '/docs/en_US/forms/' | relative_url }}">Form</a></li>
-        <li><a href="{{ '/docs/en_US/application-market/' | relative_url }}">Application Market</a></li>
-      </ul>
-    </li>
   </ul>
 </nav>
 

index.md

@@ -7,11 +7,6 @@ title: ModelEngine 应用工程文档
 
 欢迎使用 ModelEngine 应用工程文档。本仓库包含 ModelEngine 平台应用工程相关的完整文档。
 
-## 文档语言
-
-- [中文文档](docs/zh_CN/)
-- [English Documentation](docs/en_US/)
-
 ## 文档目录
 
 ### 模型接入