Jorijn: "there is no need to do a global cap anymore, the cap should be
128 per available account". `--concurrency` no longer defaults to 128:
the limits are each OAuth account's 128 (and the local login's), every
driver's counted, an API seat's own REVIEW_GATES_API_CONCURRENCY, and
free memory. `--concurrency N` still caps the machine when given; a value
below 1 is a usage error.
The dump's args.concurrency is null then. The board's driver settings
read `128 per account`, which every driver's `seats` shows as that
driver's width, and the `seats` header says a width is that driver's cap.
The Scheduler test runs 300 passes on two accounts: 256 at once, 128 each.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>