ci: add unit test gate for scripts

[castrojo]

Summary

Adds a CI test workflow running npm test on PRs and pushes that touch scripts/, package.json, or package-lock files.

Closes #942

[castrojo]

Final-review audit (K3) found two defects that would have kept this gate red; fixed in 49c3719 on this branch:

1. Bogus action pin (fatal): actions/setup-node@5fda3b95a4ea91299a34e894583c3862153e4b97 does not exist upstream — gh api repos/actions/setup-node/commits/5fda3b95... returns "No commit found for SHA". Every run would fail at job setup. Repinned to the real v7.0.0 (820762786026740c76f36085b0efc47a31fe5020, verified via gh api repos/actions/setup-node/git/refs/tags/v7.0.0), the same pin every other workflow here uses.
2. Suite not hermetic in a clean checkout (fatal): PortalContributors.tsx:6 imports @site/static/data/portal-contributors.json (gitignored, generated) at module scope; the three portal test shims read it with an unguarded readFileSync. Simulated actions/checkout state (the three gitignored data files removed): 5 tests fail, 920/925. The shims now resolve a missing @site JSON to { unavailable: true } — the data contract these components already implement. Clean-tree and dirty-tree runs both pass 925/925 on node v24.18.1.
3. Also added merge_group: (one line, pages.yml precedent) so the gate can run where merges actually land — this repo merges via the queue.

actionlint 1.7.7 clean; eslint/prettier clean on touched files. Workflow remains a sensitive path — maintainer review before merge per AGENTS.md.

[hanthor]

The hermetic-shim fix is the valuable part here — I hit that exact failure independently. Three notes on the workflow.

The shim fix is real

Before touching any PR, I ran the suite on unmodified main at 0b052ae:

$ npm run test:coverage
ℹ tests 925
ℹ pass 920
ℹ fail 5

test at scripts/portal-static-render.test.js:204:1
✖ PortalContributors renders graceful unavailable fallback when data is unavailable or empty
  Error: ENOENT: no such file or directory, open '.../static/data/portal-contributors.json'

All 5 failures were that one missing gitignored artifact, across portal-page-loading, portal-prototype-page and portal-static-render. Seeding echo '[]' > static/data/portal-contributors.json gives 925 / 925 / 0. So this is not hypothetical — a clean checkout fails the suite today, and the fs.existsSync(target) ? ... : { unavailable: true } change is exactly right. The docs/skills/component-testing.md note is a good capture of the rule.

1. npm ci --legacy-peer-deps is unnecessary and masks real conflicts

pages.yml uses plain npm ci, and plain npm ci works on this tree:

$ npm ci
(exit 0)

I also ran it cleanly on the #1215 merge, which adds a new dependency. Please drop --legacy-peer-deps so the two workflows agree and a genuine peer conflict fails loudly rather than being silently downgraded.

2. The gate is weaker than the one in pages.yml

This runs npm test, which is:

"test": "node --test \"scripts/**/*.test.js\""

pages.yml already runs npm run test:coverage, which is the same suite plus --test-coverage-lines=60 --test-coverage-functions=60 --test-coverage-branches=60. So a PR can pass this new required-looking gate while regressing coverage below the threshold, and only find out in the Pages build. Using npm run test:coverage here makes the fast gate the authoritative one.

3. The paths: filter excludes the source the tests cover

    paths:
      - "scripts/**"
      - "package.json"
      - "package-lock.json"
      - ".github/workflows/test.yml"

But the portal tests this PR just repaired live in scripts/ and load components from src/:

// scripts/portal-static-render.test.js
const rel = id.slice("@site/".length);   // resolves .ts/.tsx out of src/

So a PR that only touches src/components/portal/*.tsx — #1211 and #1228 among the currently open ones — does not trigger this workflow, even though scripts/portal-*.test.js is precisely what would catch a break. Adding src/** to both paths: blocks closes that hole.

None of this is blocking; the workflow is correct as far as it goes and Run scripts unit tests is green on this PR.

---

Generated by Claude Code