chore: migrate release tooling from semantic-release to changesets

[designcode]

What

Migrate release tooling from semantic-release to Changesets, drop commitlint, and sweep unused dev deps.

Release flow (Changesets)

• Add @changesets/cli + @changesets/changelog-github and .changeset/config.json (public access, GitHub changelog, baseBranch: main). Set package.json version to the real base 3.3.0.
• Rework release.yaml: stable releases run on push to main via the changesets action (Version Packages PR → publish → v<version> tag + GitHub release → binaries + Homebrew). Beta prereleases publish an npm snapshot to the beta dist-tag on manual workflow_dispatch only.
• Delete the release-branch flow (sync-release-to-main.yaml).
• npm publishing stays on OIDC / provenance (auth unchanged); keeping the release.yaml filename preserves the trusted-publisher config.

Cleanup

• Remove semantic-release (config, dep, script).
• Remove commitlint (@commitlint/cli, @commitlint/config-conventional, the config block, and the .husky/commit-msg hook) — versioning no longer depends on commit messages.
• Remove conventional-changelog-conventionalcommits (orphaned by the semantic-release removal).

Seed changesets

Two changesets capture the unreleased commits on main since v3.3.0, so the first Changesets release cuts 3.4.0:

• minor — buckets rebase / buckets merge commands (feat(buckets): add fork rebase and merge commands #119)
• patch — buckets create --enable-snapshots fix (fix(buckets): read camelCased enable-snapshots flag in create #120)

Verified

Build ✓; tag format stays v<version> (verified locally — keeps install.sh / update-homebrew.sh working); changeset status → 3.4.0; no lingering semantic-release / commitlint references. Merging this PR is a safe no-op until the Version Packages PR is merged.

Post-merge admin (not code)

• Retire the now-unused release branch (+ any branch protection referencing it).
• Contributors now add npx changeset per change.

🤖 Generated with Claude Code

---

Note

Medium Risk
Touches the full release and publish pipeline (npm provenance, tags, binaries, Homebrew); runtime CLI code is unchanged but a misconfigured workflow could block or mis-ship releases.

Overview
Replaces semantic-release with Changesets for versioning and npm/GitHub releases, anchored on main instead of a separate release branch.

Adds .changeset config (GitHub changelog, public publish) plus seed changesets for the pending patch (--enable-snapshots fix) and minor (buckets rebase / merge) so the first automated cut can land at 3.4.0. package.json gains changeset, version-packages, and release scripts wired into changesets/action in release.yaml.

release.yaml now opens/updates the Version Packages PR on pushes with pending changesets, and only runs integration tests immediately before publish when no changesets remain. Stable publish still drives binary builds and Homebrew updates (now gated on main). A new manual beta job publishes snapshot prereleases to npm’s beta tag without git tags or GitHub releases.

Removes the sync-release-to-main workflow and drops the commitlint husky commit-msg hook so releases no longer depend on conventional commit messages.

^{Reviewed by Cursor Bugbot for commit d675ecf. Bugbot is set up for automated code reviews on this repo. Configure here.}

[cursor]

Cursor Bugbot has reviewed your changes using default effort and found 1 potential issue.

^{❌ Bugbot Autofix is OFF. To automatically fix reported issues with cloud agents, enable autofix in the Cursor dashboard.}

Want higher recall? High effort reviews run extra passes and find more bugs. A team admin can switch effort levels in the Cursor dashboard.

^{Reviewed by Cursor Bugbot for commit 6280175. Configure here.}