connect-pg-simple keeps a recurring pruneSessions timer that calls pool.query on its pool. makeApiServer created the store with the shared KyselyPgPool but never closed it, so the timer kept running after shutdown. In tests this leaked a setInterval per makeMockedServer() call that fired pool.query on the harness's already-closed pinned connection after each test, logging "Failed to prune sessions: Client was closed and is not queryable" indefinitely and hanging the test worker — the loop that forced the manual cancellation of CI run 27951870325. Hold a reference to the store instance and call its close() in the shutdown path. ownsPg is false (we pass in our own pool), so close() only stops the prune timer and won't end the shared pool. Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>