* to get more diagnostic information than just
  "unexpected EOF while looking for matching `''"
* use that mode in GitLab CI/CD

* create coverage report with `coverage xml`
* add coverage.xml as artifact
* exclude tests and JS from coverage in SonarQube

* also add `uv.lock` to gitignore
* remove `package.json` from gitignore, because hatchling bases its
  default list of ignore/include files on the VCS ignore files

* use more modern test fixtures that take care of initializing the
  app and extensions automatically
* throw out some tests

* concentrate the configuration of all calls in one place