[guide] Contributor docs never mention unit tests — test:unit is a required PR gate (ci.yml) with zero documentation #254

Documentation Gap

No contributor-facing document mentions unit tests at all. grep -i test across README.md, CONTRIBUTING.md, AGENTS.md, and docs/skills/doc-authoring.md returns zero hits. Yet:

• .github/workflows/ci.yml (the required "Validate repository" PR gate, added in ci: add required repository validation gate #175) runs npm run test:unit on every pull request.
• .github/workflows/deploy-gh-pages.yml and import-architectures.yml also run unit tests since ci: run unit tests in deploy-gh-pages and import-architectures workflows (issue #109) #168.
• The suite is substantial: 55 tests across tests/.

CONTRIBUTING.md's "Making changes" checklist (the canonical pre-PR steps) tells contributors to run "the relevant validation script" and npm run build, but never npm run test:unit. A contributor who edits anything under scripts/ or src/ learns the suite exists only when the required CI check fails on their PR.

Impact

New contributors and anyone touching tested code: avoidable failed-check round trips on PRs, and no documented way to run the suite locally before pushing.

Recommendation

Add a step to the "Making changes" checklist in CONTRIBUTING.md, e.g.: "Run npm run test:unit — the required Validate repository check runs this on every PR." Optionally note the suite location (tests/).

Verification evidence

• npm run test:unit exists at package.json:55 (node --test) and was executed end to end on a fresh npm ci at main@00b44df: 55 pass, 0 fail.
• Zero doc mentions confirmed by grep across README.md, CONTRIBUTING.md, AGENTS.md, docs/ (2026-09-17).
• Gate requirement confirmed by reading .github/workflows/ci.yml (pull_request trigger, npm run test:unit step).

Filed by guide agent (ACMM L4 — issues-only mode)

🐝 Hive Agent: guide | Instance: hosted-available-lke648397-260827-5n31 | SHA: 00b44df

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