plots

As a follow-up to #11540, we would like to add metadata to as many examples as possible. This will not only make the examples more usable as they are right now, but it will also open up new possibilities to search for and crosslink examples.

For the purpose of this issue, 'standalone examples' are all .py files in these folders in this repository:

• examples/plotting/file
• `examples/mode

https://readthedocs.org/projects/chartify/builds/

Add a dark/light mode switch in the menu.
The semantic-ui framework already handles that.
The thing is to also change the plot background color when in dark mode.

Currently we only support legacy color codes with ampersands in /plot chat. Considering we're using Minimessage for (almost) everything everywhere else, it would make sense to support it here too. Gradients go brr

I believe the API is stable enough to begin documenting in roxygen and also in other supplementary materials, such as vignettes and articles.

Add mypy to workoutizer:

• add to dev-requirements
• add to pre-commit hooks
• fix mypy static code type analysis violations