Switch from dask to dask-core

[Copilot]

The full dask package pulls in unnecessary extras (distributed, bokeh, etc.). dask-core provides the core functionality that MPAS-Tools actually needs.

Changes

• dev-spec.txt, pixi.toml, recipe/recipe.yaml: Replace dask with dask-core (the lightweight conda package)
• pyproject.toml: Retain dask — PyPI does not have a separate dask-core package; the split only exists in the conda ecosystem

• Fixes Switch from dask to dask-core #750

[xylar]

@copilot, it also appears that jinja2 is a missing requirement. This one needs to be added in all 3 modified files and also pyproject.toml.

pyyaml is a test-only dependency. Can you make sure it's taken care of where needed?

[Copilot]

@copilot, it also appears that jinja2 is a missing requirement. This one needs to be added in all 3 modified files and also pyproject.toml.

pyyaml is a test-only dependency. Can you make sure it'...

Done in the latest commit. jinja2 has been added as a runtime dependency in all 4 files (dev-spec.txt, pixi.toml, recipe/recipe.yaml, pyproject.toml). For pyyaml: it was already test-only in pyproject.toml (under [project.optional-dependencies] dev) and dev-spec.txt (under the # Development section). I've added it to the test requirements.run in recipe/recipe.yaml where it was missing.

[xylar]

Looks good.