A concurrency slot is charged per job, not per core, and the account's cap is
the scarce resource: standard runner minutes are free and unlimited on a public
repository. Two paths spent slots that bought nothing.
The unit matrix ran eight fixed shards averaging 6.5 minutes each, 3384
job-slots a day and 68% of all slot demand, while the arm pool queued 10.5
minutes at p95 — the queue was the oversharding. Five shards run the same work
in ~10.5 minutes each for three fewer slots per run.
Bun profile persistence escalated to all six platforms on `config/`,
`resources/` and `.github/` wholesale, which took 36.5% of the last 1100
commits through the full matrix where a platform-flavoured predicate takes 19%.
A pull request now qualifies one platform unless the change is platform-
flavoured, and the push to main re-qualifies all six, so an unescalated miss
surfaces minutes after merge rather than at the next cron. Missing changed-file
evidence and an unavailable dependency graph still fail closed to all six.
* ci: stage heavy checks and measure affected-test selection
* fix(ci): exercise the real Git boundary in unit selection planning
* Harden review cancellation and CI demand reporting
Neil