The tracker opens its PR and then labels it, so a new tracker PR starts
two build runs at once. The second cancelled the first, whose always-run
`result` job then failed and left a red required check on the PR (#901)
until the surviving run finished. The tracker also force-pushes every two
hours, which would cancel long builds the same way the sync branches did.
Treat auto/track-branches like auto/sync-*: the newer run waits and
reuses the finished build's artifacts.
Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>
