Consider adding back conda instructions to contributing

[VeckoTheGecko]

@danliba has been encountering difficulty installing Pixi on DKRZ - and he would like to run a development environment there. I have looked through the Levanthe docs for Pixi and there is no mention - leading me to think that Pixi support on dkrz compute hasn't really been tested. @willirath has also mentioned that the setup on DKRZ is quite messy (environments within environments within .... within ...).

If DKRZ is not willing to sort out Pixi support - I think it might be worth adding back conda instructions in a way that has no maintenance burden. This can be done by creating a local pre-commit hook that when pixi.toml is changed, it generates a pixi export that can be read in my conda and saves that to a different file. Along the lines of what is done for the RTD setup

[danliba]

Conda environment creation instructions for DKRZ :
https://docs.dkrz.de/doc/levante/code-development/python.html

[danliba]

DKRZ support system:
https://docs.dkrz.de/doc/getting_started/user-support/index.html

[willirath]

I'd rather not re-establish conda based instructions again, but fix (or figure out ?) the DKRZ workflow. I'll use / support using the DKRZ for dev / testing in the future and streamlining our dev workflows there would help in many of my projects.

[VeckoTheGecko]

I'd rather not re-establish conda based instructions again

100% agreed 🪄

[willirath]

geomar-od-lagrange/2025_dkrz_setup#1 has a (WIP) recipe that provides a parcels dev kernel at the DKRZ: https://github.com/geomar-od-lagrange/2025_dkrz_setup/blob/6a6b7970f25fd4e30afc5c5954692829c43717d1/scripts/setup_parcels_dev_env.sh

Still depends on #2272 though and needs an pixi add ipykernel.

[VeckoTheGecko]

Awesome! Thanks for looking at this @willirath . I htink the main thing is fixing #2272 - which either way won't require re-introducing conda. Closing!