add argument to modify hover box position/direction

Right now developers can't modify the hover box position respective to the point the user is hovering. The hover box position is determined by:

• The numbers in the "transform=translate(valuex, valuey)" argument of the g element with className="hovertext": https://github.com/plotly/plotly.js/blob/master/src/components/fx/hover.js#L1200
• The shape specified in d in the path element (for the triangle orientation): https://github.com/plotly/plotly.js/issues/7278

https://github.com/user-attachments/assets/0634d079-b4eb-4325-af67-d13ac0fc6ba1

Desired behavior:

• Some argument like dcc.Tooltip direction: https://dash.plotly.com/dash-core-components/tooltip#tooltip-properties
• It should also allow diagonal/combined positions ("bottom+right")

# the python way
fig.update_traces(hoverbox_direction="right")
fig.update_traces(hoverbox_direction="left+top")

从 src/components/fx/hover.js 中 className="hovertext" 的 g 元素及其 transform 附近开始，然后查看 issue #7278，了解 hover 三角形的方向。定义方向参数应如何映射到 hover 框和三角形，包括 "left+top" 这样的组合方向；当调用方可以通过所请求的 trace 配置选择这些位置时，即表示完成。