[Feature] Double-click to preview images，Special real-time rendering

[adrve]

Many Chinese users really need this simple yet essential feature.

1、Support double-click to preview/close images, scroll the mouse wheel to zoom in/out, and drag to view obscured areas after zooming in.

2、Enable a three-column layout: directory on the left, document editing in the middle, and real-time preview on the right.

1、添加双击鼠标预览/关闭图片，滑动鼠标中键可以放大缩小图片，放大图片后可以拖拽查看被遮挡的地方。 2、开启三栏，左边目录，中间写文档，右边实时预览。