ci: evaluate git-cliff release automation (cd.yaml)

[hasansezertasan]

Context

PR #16 adds a cd.yaml (Continuous Deployment) that, on a v*.*.* tag push, generates a changelog with git-cliff (orhun/git-cliff-action) and drives a GitHub release.

Design/decision issue — this changes the release flow and needs new config, so let's agree the shape before implementing.

Open questions

• Relationship with existing workflows. publish.yaml (PyPI) and docs.yaml both trigger on release: published. Does cd.yaml (tag-triggered) create the release that then triggers those, or do we consolidate? Need one coherent release story.
• git-cliff config. Requires a [tool.git-cliff] section in pyproject.toml (commit parsing, changelog template). None exists yet.
• Changelog destination. Source writes docs/CHANGELOG.rst — do we want a committed changelog file, release-notes-only, or both?
• Trigger model. Tag-push vs. the current release-published flow (Litestarification #16's CONTRIBUTING also referenced a prepare_release.py script we did not adopt).

Proposed tasks

• Decide the release flow (tag → cd → release → publish/docs)
• Add [tool.git-cliff] config
• Add .github/workflows/cd.yaml (SHA-pinned — note Litestarification #16 uses orhun/git-cliff-action@main, a moving ref we must pin; least-privilege contents: write for release creation)
• Reconcile with publish.yaml / docs.yaml