Cut a release

For maintainers. Work for the next release happens on release/<version>, made from main after the last release. These steps release 0.2.0.

1. Check the branch:

   npm run typecheck && npm run build

2. Set the version, in package.json and the lockfile:

   npm version 0.2.0 --no-git-tag-version

3. In CHANGELOG.md, rename ## Unreleased to ## 0.2.0 (<date>). If the release adds migrations, bumps libfx, or needs a step by hand, open its section with Before upgrading.

4. Commit, merge into main, and push:

   git commit -am "Release 0.2.0"
   git switch main && git merge --ff-only release/0.2.0 && git push

5. Start the next release's branch:

   git switch -c release/0.3.0 && git push -u origin release/0.3.0

The release workflow then typechecks and builds main, checks that no shipped migration changed, tags v0.2.0, and publishes a GitHub Release with its changelog section as the notes. If a check fails, or the changelog has no section for the version, nothing is tagged or published.

• A prerelease, such as 0.3.0-rc.1, is the same steps with that version. It is published as a prerelease.
• A fix to a release goes on release/0.2.1, made from main, and is merged into the open release branch after.

How versions, tags, and migrations fit together is in Releases and updates.