dateutil dependency can't be resolved

[Schroedingberg]

I was just trying to start a project from scratch.
So I did
uv run falco start-project [NAME]

Then I ran
uv run just setup
which says

Uninstalled 1 package in 0.45ms
Installed 1 package in 0.84ms
Traceback (most recent call last):
  File "/home/aaron/.local/bin/just", line 4, in <module>
    from just.__main__ import main
  File "/home/aaron/.local/share/uv/tools/just/lib/python3.12/site-packages/just/__init__.py", line 25, in <module>
    from just.date import yesterday, days_back
  File "/home/aaron/.local/share/uv/tools/just/lib/python3.12/site-packages/just/date.py", line 3, in <module>
    from dateutil.rrule import DAILY, rrule
ModuleNotFoundError: No module named 'dateutil'

Now that's where the fun begins.

uv add dateutil
  × No solution found when resolving dependencies for split (markers: python_full_version >= '3.14'):
  ╰─▶ Because there are no versions of dateutil and your project depends on dateutil, we can conclude that your project's requirements are unsatisfiable.

      hint: While the active Python version is 3.13, the resolution failed for other Python versions supported by your project. Consider limiting your
      project's supported Python versions using `requires-python`.
  help: If you want to add the package regardless of the failed resolution, provide the `--frozen` flag to skip locking and syncing.

I've tried a with different python versions, but I couldn't figure out where this comes from.

[Schroedingberg]

I might have missed that I need to run falco with uv tool run to bootstrap a project.
I tried that now but that seems to fail compiling grpcio?
Seems like I need to dig deeper...