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/infographic-markdown.md

@@ -0,0 +1,120 @@
+# Infographic to Markdown
+
+> **Version:** 1.0.0 | **Author:** Fu-Jie
+
+AI-powered infographic generator that renders SVG on the frontend and embeds it directly into Markdown as a Data URL image.
+
+## Overview
+
+This plugin combines the power of AI text analysis with AntV Infographic visualization to create beautiful infographics that are embedded directly into chat messages as Markdown images.
+
+### Key Features
+
+- :robot: **AI-Powered**: Automatically analyzes text and selects the best infographic template
+- :bar_chart: **Multiple Templates**: Supports 18+ infographic templates (lists, charts, comparisons, etc.)
+- :framed_picture: **Self-Contained**: SVG/PNG embedded as Data URL, no external dependencies
+- :memo: **Markdown Native**: Results are pure Markdown images, compatible everywhere
+- :arrows_counterclockwise: **API Writeback**: Updates message content via REST API for persistence
+
+### How It Works
+
+```mermaid
+graph TD
+    A[User triggers action] --> B[Python extracts message content]
+    B --> C[LLM generates Infographic syntax]
+    C --> D[Frontend JS loads AntV library]
+    D --> E[Render SVG offscreen]
+    E --> F[Export to Data URL]
+    F --> G[Update message via API]
+    G --> H[Display as Markdown image]
+```
+
+## Installation
+
+1. Download `infographic_markdown.py` (English) or `infographic_markdown_cn.py` (Chinese)
+2. Navigate to **Admin Panel** → **Settings** → **Functions**
+3. Upload the file and configure settings
+4. Use the action button in chat messages
+
+## Configuration
+
+| Parameter | Type | Default | Description |
+|-----------|------|---------|-------------|
+| `SHOW_STATUS` | bool | `true` | Show operation status updates |
+| `MODEL_ID` | string | `""` | LLM model ID (empty = use current model) |
+| `MIN_TEXT_LENGTH` | int | `50` | Minimum text length required |
+| `MESSAGE_COUNT` | int | `1` | Number of recent messages to use |
+| `SVG_WIDTH` | int | `800` | Width of generated SVG (pixels) |
+| `EXPORT_FORMAT` | string | `"svg"` | Export format: `svg` or `png` |
+
+## Supported Templates
+
+| Category | Template | Description |
+|----------|----------|-------------|
+| List | `list-grid` | Grid cards |
+| List | `list-vertical` | Vertical list |
+| Tree | `tree-vertical` | Vertical tree |
+| Tree | `tree-horizontal` | Horizontal tree |
+| Mind Map | `mindmap` | Mind map |
+| Process | `sequence-roadmap` | Roadmap |
+| Process | `sequence-zigzag` | Zigzag process |
+| Relation | `relation-sankey` | Sankey diagram |
+| Relation | `relation-circle` | Circular relation |
+| Compare | `compare-binary` | Binary comparison |
+| Analysis | `compare-swot` | SWOT analysis |
+| Quadrant | `quadrant-quarter` | Quadrant chart |
+| Chart | `chart-bar` | Bar chart |
+| Chart | `chart-column` | Column chart |
+| Chart | `chart-line` | Line chart |
+| Chart | `chart-pie` | Pie chart |
+| Chart | `chart-doughnut` | Doughnut chart |
+| Chart | `chart-area` | Area chart |
+
+## Usage Example
+
+1. Generate some text content in the chat (or have the AI generate it)
+2. Click the **📊 Infographic to Markdown** action button
+3. Wait for AI analysis and SVG rendering
+4. The infographic will be embedded as a Markdown image
+
+## Technical Details
+
+### Data URL Embedding
+
+The plugin converts SVG graphics to Base64-encoded Data URLs:
+
+```javascript
+const svgData = new XMLSerializer().serializeToString(svg);
+const base64 = btoa(unescape(encodeURIComponent(svgData)));
+const dataUri = "data:image/svg+xml;base64," + base64;
+const markdownImage = `![description](${dataUri})`;
+```
+
+### AntV toDataURL API
+
+```javascript
+// Export as SVG (recommended)
+const svgUrl = await instance.toDataURL({
+    type: 'svg',
+    embedResources: true
+});
+
+// Export as PNG
+const pngUrl = await instance.toDataURL({
+    type: 'png',
+    dpr: 2
+});
+```
+
+## Notes
+
+1. **Browser Compatibility**: Requires modern browsers with ES6+ and Fetch API support
+2. **Network Dependency**: First use requires loading AntV library from CDN
+3. **Data URL Size**: Base64 encoding increases size by ~33%
+4. **Chinese Fonts**: SVG export embeds fonts for correct display
+
+## Related Resources
+
+- [AntV Infographic Documentation](https://infographic.antv.vision/)
+- [Infographic API Reference](https://infographic.antv.vision/reference/infographic-api)
+- [Infographic Syntax Guide](https://infographic.antv.vision/learn/infographic-syntax)