Ability to use python-dbg as a python specifier

[adrinjalali]

Summary

In the context of working on numpy, I ended up with a CI using python3-dbg failing. In order to reproduce that locally, I would have liked to have a uv venv -p python312-dbg or similar to have an environment with that python.

Instead, I had to compile python-dbg on my machine, and use that binary as a python specifier.

To be clear, this is what I had to install: https://aur.archlinux.org/packages/python-dbg

Example CI run I'm trying to reproduce: https://github.com/numpy/numpy/actions/runs/12927283485/job/36052517088?pr=26018

Example

uv venv -p 312-dbg /path/to/venv