cypress/packages/runner

Runner

This is an old package, deprecated in favor of @packages/app. It has two remaining responsibilities before it can be entirely removed:

1. Bundles @packages/reporter and @packages/driver via webpack. Once those can be directly imported to @packages/app, we can remove this.
2. Bundles styles for @packages/reporter, loaded in main.scss. Ideally, reporter should import its own styles.
3. Some existing tests in cypress/e2e should be migrated to @packages/app/cypress/e2e/runner.