当X轴为分类类型时，平移交互会抖动

### What problem does this feature solve?
当X轴为分类类型时，平移交互不像线性类型那样流畅。尤其是当一屏数据不多的时候，平移的时候会很抖。
https://codepen.io/chenyiqiao/pen/mddvgLY

### What does the proposed API look like?
无

Start with the linked CodePen reproduction and compare panning behavior for categorical and linear X axes, especially when only a small amount of data is visible. Done means categorical-axis panning is as smooth as linear-axis panning without jitter; the payload names no source files or tests to inspect.

Written by the indexing model from the issue text.