Standard and Pro do not silently run unsupported work without isolation. They
emit a complete
cannot_run receipt when required capability is unavailable.
Ultra is the appropriate tier when a full build, broad dependency restore, or
adversarial security analysis is required.
Credits are pooled per workspace. Usage records attribute requested/effective
tier, model/provider route, execution, and receipt cost to the repository and
actor. Reservations prevent concurrent jobs from overspending the workspace
pool; settlement releases unused reservations.