Document `cpa.config.json` vs `cna.config.json` for Python

[ulises-jeremias]

Summary

Python-specific config: pyproject, uv, ruff, pytest hooks.

CNA mapping

CNA: cna.config.json consumed by core config.ts.

Acceptance criteria

• Side-by-side doc
• Examples for a minimal FastAPI/Flask/CLI template stub

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

#6