Fixes the fixtures the first verify run falsified: the sensor's start-up seed
made one-tick ratios meaningless (compare settled infos and the settled ping
extra), launch drag moves a cloud less than its velocity, and the vent's own
velocity is read when the cloud is added, not after it has drifted. Test-only;
builds.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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