Custom labels on axis

I wanted to put some labels on top of the y axis (similar to TradingView, see the video), but right now there is no way of getting axis thickness, so I can't make it look pretty.

https://github.com/user-attachments/assets/81480f0f-4b37-4ad5-b489-f47d952583c9

**Describe the solution you'd like**

Possible solutions:
1. Expose `x_axis_thickness/y_axis_thickness` from `PlotMemory`, however it will be hard to get the same label formatting that we get from `x_axis_formatter/x_axis_formatter`
2. Implement these labels internally and expose them in `Plot` API, but I'm not sure that anyone besides me needs them

**Additional context**
That's what I got with an exposed `y_axis_thickness`

https://github.com/user-attachments/assets/c6b347a9-6107-40ca-9d44-0d42ee13a856