Every test layer in one command and in CI

[hammadmajid]

Part of #3

Question

Wire every test layer into one command and into CI, and hold the speed bar.

• pnpm test runs unit and integration across the monorepo through Turborepo with caching; pnpm test:e2e runs Playwright for web and landing against a locally started server.
• CI runs both on every push to main and every pull request, with browser caching and sharding as the research found.
• Measure: local unit and integration under ten seconds, full CI under five minutes. Record the numbers in the README.
• Decide and record where Maestro will slot in once the phone app has more screens.