fix(changelog): write CHANGELOG.md and backfill the history

[GSTJ]

This repo has shipped 9 releases and has no CHANGELOG.md. release-it's conventional-changelog plugin had no infile, so it generated a changelog for each release body and threw it away. Two of those bodies came out empty while the range under them contained a breaking change.

Infile

infile: "CHANGELOG.md" plus a backfill of the 9 existing releases, generated from the commits. The plugin prepends, so once the file exists the history below the newest section is never rewritten.

The config moves from the release-it key in package.json to .release-it.mjs, because the type list now lives in tools/changelog-preset.mjs and JSON can't import it. tools/changelog-check.mjs reads the same list.

Sections

files publishes src and lib side by side, so the split is whether a type can change what npm hands a consumer:

renders	why
feat, fix, perf, revert	the stock set
build	bob's targets and tsconfig.build.json decide what lands in lib/
refactor	rewrites src/ and lib/, both published
chore	dependency and config moves ship
docs	README.md is inside the tarball

hidden	why
ci	.github/ is not in files
style	oxfmt touches published src/, whitespace only
test	!**/__tests__ is excluded from files

The four new ones are effect: "changelog". They render without entering the bump count, so a release of nothing but build: commits is still a patch. Only feat, fix, perf and revert can raise a version.

Backfill

Where the git history and a published release body disagree, the file follows the history.

0.2.2 and 0.3.1 each shipped a feat!: and each published a body with no sections at all. 0.2.2 went out as a patch off a breaking change. Both now carry their ⚠ BREAKING CHANGES heading. No tag was moved and no release body was edited.

0.4.0 and 1.0.0 were written by hand and say more than the commits do (the peer version table, the new-architecture steps, the return-value change on magicToast.show()). Their generated sections carry a link to the release notes.

Check

pnpm run changelog:check builds a throwaway repo with 12 commits, one per type, 3 of them breaking, renders it through the real preset and asserts on what comes back. ci is hidden and the ci!: commit's breaking note still has to surface.

The check carries its own copy of the policy, so the two disagreeing is a failure. Derived from the preset, every assertion would be a tautology: hide a section and the check quietly redefines what it expected. The negative control in the image is what that failure looks like.

The bump is asserted too: feat! major, feat minor, fix patch, and build/refactor/chore/docs together no release at all.

Wired into Branch Checkup as extra-command.

Release

npm latest is 1.0.0 and the 16 commits since the tag are tooling. Verified by rehearsing on a throwaway clone with publish, push and the GitHub release all off: 1.0.0 -> 1.0.1, the new section prepends, and git diff shows zero lines removed from everything below it.

The annotated tag now carries the same section as the changelog and the release body. git's default tag cleanup strips every line starting with #. That was eating all the headings. tagArgs pins --cleanup=verbatim.