release: v0.5.1

[musharna]

Why now

Zenodo's GitHub integration has been enabled for this repository. Zenodo only archives
releases published after the toggle is switched on — existing tags are not picked up
retroactively — so a new release is what actually mints the DOI.

This is not a no-op release. It ships the CITATION.cff 0.4.0→0.5.0 correction (the file claimed a version the project had not shipped for a month), .zenodo.json, and the new citation version gate.

What

file	change
pyproject.toml	0.5.0 → v0.5.1
CITATION.cff	version + date-released bumped to match
CHANGELOG.md	new [0.5.1] section

The citation CI job added earlier today enforces that CITATION.cff and
pyproject.toml agree, so this PR cannot go green with a half-done bump.

After merge

Pushing the v0.5.1 tag triggers the release workflow (PyPI via Trusted Publishing) and the
GitHub release, which is what Zenodo listens for. That step is irreversible — a PyPI
version cannot be reused — so I have not tagged anything. Say the word and I will, or
tag it yourself:

git checkout main && git pull
git tag v0.5.1 && git push origin v0.5.1

Once Zenodo mints the DOIs, send them over and I will add the badges and the
identifiers: block to CITATION.cff.

🤖 Generated with Claude Code