feat: Add entrypoint for anemoi-datasets to PyEarthTools

[HCookie]

Add entrypoint for anemoi.datasets.source to make use of PyEarthTools pipelines.

Allows for usage of

name: pyearthtools_to_anemoi
description: PyEarthTools Pipeline converted to Anemoi
attribution: PyEarthTools

dates:
    start: '2025-11-10T00:00:00'
    end: '2025-11-12T00:00:00'
    frequency: 1h

input:
    pyearthtools: # Use the pyearthtools input object
        pipeline: /PATH/TO/PIPELINE.yaml

TODO @tennlee

• Review docs
• Review license

[coveralls]

Pull Request Test Coverage Report for Build 19430510647

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
• To avoid this issue with future PRs, see these Recommended CI Configurations.
• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 0 of 0 changed or added relevant lines in 0 files are covered.
• 34 unchanged lines in 1 file lost coverage.
• Overall coverage increased (+0.4%) to 63.223%

---

Files with Coverage Reduction	New Missed Lines	%
packages/data/src/pyearthtools/data/catalog.py	34	66.01%

Totals
Change from base Build 19354196491:	0.4%
Covered Lines:	10013
Relevant Lines:	15459

---

💛 - Coveralls

[tennlee]

Looks great, I have minor feedback only, let me know when it's ready to merge and I'll happily do so. Please take the feedback as suggestions only and just let me know when you are ready for me to merge it.

[tennlee]

I have left some suggestions. Let me know when you think it's ready. I don't have any objections to the merge, just things you might like to consider.

[tennlee]

There are some very tiny issues with the docs, probably easiest if I just fix them up afterwards, as I can try a few things and test them locally.