[3623286] Add automated test coverage gate

Ivan Hrynenkorequested to merge
feature/3623286-test-coverage into 2.x

Drupal.org issue: #3623286

Summary:

  • Adds Unit and Kernel coverage across Entity Activity and its optional submodules.
  • Enforces a minimum 80% production PHP line-coverage gate in GitLab CI.
  • Retains the existing document-root and subdirectory browser-test matrix.

Merge request reports