GitHub Actions CI pipeline

[mathieusouflis]

What to build

Replace the placeholder CI/release workflow stubs with a real, working pipeline.

Set up:

• CI workflow (ci.yml): triggers on push to main and on PRs targeting main
  • Job 1: lint + type-check
  • Job 2: tests (Vitest)
  • Job 3: build (tsup) — depends on jobs 1 and 2
  • Job 4: Storybook build — depends on job 3
• Release workflow (release.yml): triggers on push to main
  • Uses Changesets action: accumulates changeset files into a Version PR
  • On Version PR merge: bumps package.json version, updates CHANGELOG.md, publishes to npm
• Commitlint workflow already exists — verify it works with the actual commit conventions in use

The workflows replace the placeholder echo steps in the existing CI/release stubs.

Acceptance criteria

• A PR to main triggers lint, type-check, test, build, and Storybook build — all passing
• Merging a changeset Version PR publishes a new version to npm (verifiable in workflow logs or dry-run)
• Failed lint or tests block the build job
• Storybook build job produces an artifact (uploadable or deployable)

Blocked by

• Repo scaffold + build pipeline #2 (Repo scaffold + build pipeline)