Frontend test infrastructure is missing entirely

[mercy60]

Internal ID: #89

Imported from ISSUES.md via scripts/import-issues.mjs.

Problem Statement. frontend/package.json has no test tool. CONTRIBUTING.md references npm test that doesn't exist.

Expected Outcome. Vitest + React Testing Library scaffolding.

Acceptance Criteria.

• A page test boots successfully.

Dependencies. None.

Difficulty / Effort. Medium / M (≈ 1 day).

Labels. testing, area:frontend