Add CLAUDE.md for Claude Code

[jcschaff]

What

Adds a CLAUDE.md to guide future Claude Code sessions in this repo.

Contents

• Build/test commands — uv dev setup, ruff, mypy --strict, running the full stdlib unittest suite and a single test class, running the CLI.
• Architecture — the four-module split by dependency direction (sources.py / config.py / api.py / cli.py) and the two cross-file invariants: no bespoke config (standard CITATION.cff / .zenodo.json files), and the --execute gate living in cli.py while api.py mutating helpers stay pure.
• Conventions that matter — dry-run-by-default, version-label-vs-source-tag precedence and its tests, the sandbox smoke test guarding against unversioned Zenodo API drift, and the ruff lint config.

Points at README.md and skill/SKILL.md rather than duplicating them.

🤖 Generated with Claude Code

https://claude.ai/code/session_01BZx7w9BexQc9wWU5JoHYaF