Configure Ruff (lint + format) at workspace root

[ulises-jeremias]

Summary

Single Ruff config for all packages.

CNA mapping

CNA: eslint.config.cjs + Prettier.

Acceptance criteria

• Ruff config in root pyproject.toml or ruff.toml
• uv run ruff check and ruff format --check documented
• Applies to packages/**

Blocked by

none

Blocks

none

Reference

Parity matrix (workspace): knowledge/create-python-app-parity-matrix.md
Reference repo: https://github.com/Create-Node-App/create-node-app

Parent epic

#3