Run the site theme tests in CI

[Muawiya-contact]

#108 added three tests in site/tests/theme-root.test.js and an npm test script. They pass locally, but CI never runs them.

The site job in .github/workflows/ci.yml currently runs:

- run: npm ci
- run: npm run lint
- run: npm run build

Add - run: npm test after lint and before the build. This keeps a future theme regression from merging with a green build.

Done when: all three tests run on a pull request, and a failing assertion fails the site job.

cd site
npm ci
npm test

Confirmed on 8abd5cb: three local tests pass; the workflow has no site test step. This is separate from #109, which covers Rust desktop tests.

[LouisDeconinck]

I'll take this one — adding npm test to the site job so the theme tests run on PRs.

[LouisDeconinck]

Looking into this, it seems the step is already on main — the site job in .github/workflows/ci.yml currently runs:

- run: npm ci
- run: npm run lint
- run: npm test
- run: npm run build

The npm test line was added by #108 itself (commit abff933), so it's present in 8abd5cb too — git show 8abd5cb:.github/workflows/ci.yml shows it in the site job.

Verified on current main: cd site && npm ci && npm test runs all 7 tests (the 3 theme tests plus the 4 in releases.test.js), and node --test exits non-zero on a failure, so a failing assertion fails the job.

Unless the intent was something different — e.g. also running the tests in deploy-pages.yml, which builds the site without them — this may already be done. Happy to send that follow-up if that's what you meant.