Add ipykernel to pixi deps

[evetion]

Not sure if manifest version 5 will cause trouble.

I use VS Code for interactive development, which requires ipykernel. Since VS Code uses the pixi env, I always end up adding ipykernel in the past months. Seems like a good developer addition.

Similarly, I always limit the pyarrow version, as I otherwise get a

  File "/Users/evetion/code/Ribasim.jl/.pixi/envs/dev/lib/python3.12/site-packages/pandas/compat/pyarrow.py", line 10, in <module>
    _palv = Version(Version(pa.__version__).base_version)
                            ^^^^^^^^^^^^^^
AttributeError: module 'pyarrow' has no attribute '__version__'

I'm not sure why the CI doesn't reproduce this.

[evetion]

Ah the manifest needs #1491. Downgraded it for now.

[visr]

Seem fine to me. I'm a bit surprised about ipykernel, I use interactive Python in VSCode all the time but don't run into this. But the VSCode docs do mention it needs an ipykernel install, so let's add it.

I've also run into the pyarrow version issue. So far re-installing the pixi environment worked for me. But capping the version is probably more robust for now.