Run Playwright E2E tests in CI #22
Description
Summary
Add a GitHub Actions workflow that runs Playwright end-to-end tests on every Pull Request, ensuring UI flows are validated in a real browser context and blocking merges if failures occur.
Goals
- Execute Playwright E2E tests on every PR.
- Catch integration and UI-level regressions that unit tests miss.
- Fail CI when E2E tests fail, preventing merge.
Non-Goals
- Full browser matrix (Chromium-only acceptable for MVP).
- Visual regression tooling.
- Performance benchmarking.