StartOnly jobs previously forced DurationMS to 0 because GoSentry does
not wait for the process to exit, leaving the Statistics line stuck at
"last 0 ms, avg 0 ms". The runner already measures launch latency (time
to spawn the process) for the History detail; this now returns that
value as the run duration so the existing duration-driven stats pipeline
folds it into last/avg/max.
Sub-millisecond launches still round to 0 and are excluded from the
average, matching prior behavior.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
