Adding feature tracking operator

[Adam Gainford (A-Gainford)]

Adding feature-tracking via the Simple-Track repo (https://github.com/ParaChute-UK/simple-track), which is included as a new dependency. The feature.track operator is used to call Simple-Track, which returns three cubes per timestep: "feature_id", "feature_lifetime" and "feature_init". These can be filtered to select them for plotting with existing routines. Other data which is not currently used by CSET can be saved for further analysis. The new "feature" operator set will also be used to implement cell stats using Simple-Track with the tracking capabilities disabled (though the "feature" name may want to be changed).

Contribution checklist

Aim to have all relevant checks ticked off before merging. See the developer's guide for more detail.

• Documentation has been updated to reflect change.
• New code has tests, and affected old tests have been updated.
• All tests and CI checks pass.
• Ensured the pull request title is descriptive.
• Ensure rose-suite.conf.example has been updated if new diagnostic added.
• Conda lock files have been updated if dependencies have changed.
• Attributed any Generative AI, such as GitHub Copilot, used in this PR.
• Marked the PR as ready to review.

[James Frost (jfrost-mo)]

Thank you for this pull request, and sorry it took so long for me to get to it. I'm assuming that despite it being a draft PR it is ready for a review.

Overall it looks like a good set of changes that will nicely integrate simple-track into CSET. There are a few small issues highlighted in the comments below, but it is overall looking very good.

Please run the pre-commit checks over this code (pre-commit run --all-files) to fix a number of minor issues. These checks can be set to run on each commit by running pre-commit install.

[Adam Gainford (A-Gainford)]

Thanks for the taking a look through the code, happy with the suggestions. I assume it's okay to accept changes on the lockfiles at the bottom of the PR page but I have held off for now

[James Frost (Fraetor)]

Still need to review the feature file.

[James Frost (Fraetor)]

Is this just a reasonable upper nound for the number of features tracked?

[James Frost (Fraetor)]

Supposedly set_under is deprecated and we should be using with_extremes instead.
https://matplotlib.org/stable/api/_as_gen/matplotlib.colors.Colormap.html#matplotlib.colors.Colormap.set_under
https://matplotlib.org/stable/api/_as_gen/matplotlib.colors.Colormap.html#matplotlib.colors.Colormap.with_extremes

Given this can be set at colourway Creation maybe we should think about allowing this to be set in the colourbar file. Probably something for a different PR though.

[James Frost (Fraetor)]

Suggested change

	.DS_Store
	.DS_Store

As the pre-commit check notes, this file will need to end in a newline.

Fun fact: Strictly according to the POSIX specification a file that doesn't end in a new line isn't technically a text file.