feat: 添加Vue3环境下运行的demo

[alsdhkauuhw]

Vue3 demo

添加vue环境下通过api更改编辑器内容，可以在右侧测试接口是否支持Vue3环境

[tencent-adm]

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:x: cc
:x: alsdhkauuhw

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[github-actions[bot]]

【预览链接】

• https://cherrymd.com/pr817/examples/index.html

[github-actions[bot]]

【预览链接】

• full model
• basic
• mobile
• multiple instances
• editor without toolbar
• pure preview
• XSS（Not allowed by default）
• img wysiwyg
• table wysiwyg
• headers with auto num
• 流式输入模式（AI chart场景）
• VIM 编辑模式