Improve BaseService logging

* Show logs on test failure but suppress them if the test passes
* Make log target an injected dependency (so we can capture it, write to a file, etc)
* Pass `logDebug()` a log level and make use of different logging levels (`console.info()`, `console.error()`, `console.warn()` etc)

Start by locating BaseService and the tests that exercise its logging behavior. Review how logs are currently emitted, then verify the three requested outcomes: failed tests show logs while passing tests suppress them, the log target can be injected, and logDebug() supports distinct logging levels.

Written by the indexing model from the issue text.