Migrate Python tooling to uv and ruff

[rtibbles]

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Overview

Migrate from pip/tox/setup.py to uv, and replace flake8/black/reorder-python-imports with ruff, following the same approach as learningequality/kolibri#14457.

Complexity: Low
Target branch: main

Context

Kolibri has migrated to uv for Python version management, virtual environments, dependency resolution, and CI. The same migration should be applied across the ecosystem for consistency. Ricecooker already has yamlfmt and actionlint in its pre-commit config.

The Change

• Convert setup.py/setup.cfg to pyproject.toml with PEP 735 dependency groups
• Replace custom versioning with setuptools-scm
• Replace tox with direct uv invocation in CI
• Replace flake8/black/reorder-python-imports with ruff
• Replace pre-commit with prek
• Update CI workflows to use astral-sh/setup-uv with enable-cache: true and cache-python: true (this may need to be turned off for Windows workflows - can check on CI)
• Configure exclude-newer = "7 days" with exclude-newer-package exemption for le-utils in [tool.uv] for supply chain safety
• Add uv-lock pre-commit hook (from astral-sh/uv-pre-commit) to keep uv.lock in sync
• Update developer documentation

Acceptance Criteria

• pyproject.toml replaces setup.py/setup.cfg as the single source of project metadata and configuration
• Versioning handled by setuptools-scm
• tox.ini removed; CI uses uv directly
• Linting and formatting handled by ruff (replacing black, flake8, reorder-python-imports)
• Pre-commit uses prek
• CI workflows use astral-sh/setup-uv@v7
• exclude-newer cooldown configured in pyproject.toml
• uv-lock pre-commit hook added to .pre-commit-config.yaml
• All existing tests pass
• Developer documentation updated

References

• Migrate to uv, setuptools-scm, prek, and ruff kolibri#14457 — Kolibri uv migration (reference implementation)

AI usage

This issue was drafted by Claude Code based on the Kolibri uv migration work.