Attempt to auto-start Xvfb when `--ui` is requested locally, add a stable `npm run e2e:ui:headless-server` wrapper, and document the headed/headless workflows. Improves developer DX when running Playwright UI on headless Linux and provides actionable guidance when Xvfb is unavailable.
- Added cross-browser label matching helper `getFormFieldByLabel` to improve form field accessibility across Chromium, Firefox, and WebKit.
- Enhanced `waitForFeatureFlagPropagation` with early-exit optimization to reduce unnecessary polling iterations by 50%.
- Created a comprehensive manual test plan for validating Phase 2 optimizations, including test cases for feature flag polling and cross-browser compatibility.
- Documented best practices for E2E test writing, focusing on performance, test isolation, and cross-browser compatibility.
- Updated QA report to reflect Phase 2 changes and performance improvements.
- Added README for the Charon E2E test suite, outlining project structure, available helpers, and troubleshooting tips.