HoloDeck UV reference

Source of truth: pyproject.toml, uv.lock, and Makefile.
Setup: uv sync --all-extras
Project command: uv run holodeck --version
Focused tests: uv run pytest <test-path> -n auto
Dependencies: uv add <package>, uv add --dev <package>, uv remove <package>

Use the existing lockfile. Change dependencies only within the requested scope.
The package supports Python 3.10+. Current CI and make init use Python 3.10.
See docs/contributing.md for verification and known Makefile limitations.