"Solution": `pixi add python=3.12`, then `pixi add --pypi aider-chat` succeeds without issues.
A message like "aider-chat seems to be incompatible with python=3.13, try downgrading to python-3.12" would be great, assuming this is really the case.
I can create an issue if it helps, but really quick here's the error I was getting and some talk on discord about it:
https://discord.com/channels/1082332781146800168/12957237931...