fix: implement timeouts and failure recovery to prevent thread hanging in evaluator

[aseering]

Make the code more defensive against database connection issues, queries that fail in unexpected ways, and other sorts of test-runtime issues.

• Add timeouts such that tests that run for too long are terminated
• Add error handling such that exceptions and other errors are consistently treated as query failures, rather than potentially dropping the affected eval (resulting in a run that never reaches 100%)

[IsmailMehdi]

/gcbrun