Investigate the Use of Goroutine Leak Detector

## Task summary

- Investigate the use of a goroutine leak detector such as [`goleak`](https://github.com/uber-go/goleak) and consider adding it to Gossamer tests.

No specific files or tests are named. Start by reviewing the Gossamer test suite and the linked goleak project to assess how a goroutine leak detector could be used; done means documenting the integration decision and, if adopted, adding it to the tests with evidence that the detector is active.

Written by the indexing model from the issue text.