GalaxyTelemetryTests (ActivityListener) and GatewayGalaxyDataWriterFailClosedTests
(MeterListener, filtered only by meter and instrument name) observe every Galaxy span or
measurement in the process. They now run in a collection with parallelization disabled
(F-FU6), because a parallel driver test, or its background probe seed, polluted their counts.
The stream-cancel assertion in GalaxyDriverShutdownTests goes back to a bounded wait: the
instantaneous IsCompleted check introduced in round 1 was racy.
Refs #735
Claude-Session: https://claude.ai/code/session_01Ub9hGmYLQvn9XETzw7CMsT
Joseph Doherty