feat(infographic-markdown): add new plugin for JS render to Markdown

- Add infographic_markdown.py (English) and infographic_markdown_cn.py (Chinese)
- AI-powered infographic generator using AntV library
- Renders SVG on frontend and embeds as Markdown Data URL image
- Supports 18+ infographic templates (lists, charts, comparisons, etc.)

Docs:
- Add plugin README.md and README_CN.md
- Add docs detail pages (infographic-markdown.md)
- Update docs index pages with new plugin
- Add 'JS Render to Markdown' pattern to plugin development guides
- Update copilot-instructions.md with new advanced development pattern

Version: 1.0.0

docs/plugins/actions/index.zh.md

@@ -77,6 +77,16 @@ Actions 是交互式插件，能够：
 
     [:octicons-arrow-right-24: 查看文档](summary.md)
 
+-   :material-image-text:{ .lg .middle } **信息图转 Markdown**
+
+    ---
+
+    AI 驱动的信息图生成器，渲染 SVG 并以 Markdown Data URL 图片嵌入。
+
+    **版本：** 1.0.0
+
+    [:octicons-arrow-right-24: 查看文档](infographic-markdown.zh.md)
+
 </div>
 
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