Fix Playwright test stalling: Use non-headless mode for extension support
Root cause: Chrome extensions don't load service workers in headless mode,
causing tests to hang indefinitely waiting for serviceworker event.
Changes:
- Set headless: false in playwright-util.js (requires xvfb in CI)
- Use proper user data directory instead of empty string
- Add timeout to beforeEach welcome page wait to prevent hanging
- Add .playwright-user-data/ to .gitignore
Testing showed:
- Service worker count: 0 in headless mode
- Service worker count: 1 in non-headless mode with xvfb
- Extensions require X11 display to function properly
CI should run with xvfb-run to provide virtual display.
Co-authored-by: MarvNC <17340496+MarvNC@users.noreply.github.com>