Restore reproducible local validation #315

Parent umbrella issue: #308
Source audit: Weekly tech debt audit: dispatch - 2026-06-03
Source audit date: 2026-06-03

Original recommendation

P2 — Restore reproducible local validation: document/repair local install expectations so npm run typecheck and npm run test work from a clean checkout with npm ci.

Matched top finding

The audit could not run full tests locally because the checked-out node_modules was incomplete. CI likely installs cleanly with npm ci, but the local workspace state can mislead agents during audits/fixes.

Evidence:

• npm run typecheck failed before project checking: TS2688: Cannot find type definition file for '@testing-library/jest-dom'.
• npm run test -- --runInBand failed: sh: 1: vitest: not found.
• node_modules/.bin lacked vitest; node_modules/@testing-library/jest-dom was missing.
• Repo contains 63 test files, so this is an environment/install issue rather than absence of tests.