Fix python 3.14 and move to rattler

[chrisburr]

Mostly about picking up robotpy/crossenv#130, the rest is just general housekeeping.

Should fix conda-forge/cross-python-feedstock#98

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found some lint.

Here's what I've got...

For recipe/recipe.yaml:

• ❌ There are 1 too many lines. There should be one empty line at the end of the file.

_{This message was generated by GitHub Actions workflow run https://github.com/conda-forge/conda-forge-webservices/actions/runs/17146142308. Examine the logs at this URL for more detail.}

[conda-forge-admin]

Hi! This is the friendly automated conda-forge-linting service.

I just wanted to let you know that I linted all conda-recipes in your PR (recipe/recipe.yaml) and found it was in an excellent condition.