Deprecated — use extension-testing

Extension E2E flakiness lives inside extension-testing:

1. references/e2e.md
2. references/e2e/maintain.md
3. references/e2e/flakiness.md

POM / bad-practice audits: references/e2e/pom-antipatterns.md.

For Mobile Jest unit flakiness, use the separate flaky-test-detection skill (not this stub).