Ability to label prices

This is just an idea of a little addition that I think can be useful. It would be nice to see what is the lastest value on the volume chart, price chart and also any addplots.
Example:

- The arrows have their value as a label

- Both charts have a white box that indicates the latest price value


Start by reviewing how the price chart, volume chart, addplots, and arrow annotations are rendered; the issue does not name specific files or tests. Clarify the intended label behavior and placement for each chart element, then verify that the latest values appear consistently without obscuring the plots.

Written by the indexing model from the issue text.