feat: comprehensive Detox tests for all screens with cleanup

- Create viewshot-all-screens.test.js covering all 10 test screens
- Add testID to all ScrollViews for reliable scrolling in tests
- Add scrollViewTestID prop to TestScreenLayout component
- Remove 10 old test files (advanced-viewshot, regression, simple, etc.)
- Remove test-sequencer.js (no longer needed)
- Update test scripts to use comprehensive all-screens test by default
- Keep viewshot-basic.test.js as a quick smoke test option
- Each test: navigates, captures, scrolls to see result, validates snapshot
- Organized tests by category: Basic, Media, Advanced

Author: greweb