Define developer environment through uv

[redeboer]

This is a tracking issue

Currently, ComPWA repositories attempt to support development through several virtual environment managers, like Conda, venv, uv, and pixi. See Help developing. This has resulted in a complicated setup, such as the use of dev optional dependencies for defining developer dependencies (see also this Stackoverflow), and a larger number of constraint files that are updated through update-pip-constraints.

For managing project with Python dependencies only, it seems that uv is the way to go forward, as it allows to pin and bootstrap specific Python versions, can generate universal lock files, and provides a standard for developer dependencies.
Edit: Support for dependency groups (PEP 735) has been accepted and will be available in uv as well.

A problem remains non-Python dependencies, in particular graphviz. This is currently assumed to be installed on the system, or it is provided in the Conda/Pixi environment. Some thoughts:

• Using Pixi in addition would result in two lock files, uv.lock and pixi.lock. It also does not yet recognize [tool.uv.dev-dependencies].
• Conda does not yet work with uv. Keep an eye on conda_env installers / providers plugin hooks conda/conda#13833.

What would also be great is to ditch the .constraints/ folder and switch to a uv.lock (and/or pixi.lock) file. The lock files are fast enough that you can have direnv update the pinned dependencies without noticable speed, which would remove the hassle of syncing dependencies by hand.