Credential values keyed by normalized MJ: AI Model Vendors row id.
Static ReadonlyNoneNo platform credentials: every lookup falls through to the run's keys and the environment.
The number of model-vendor rows a platform credential resolved for.
The platform credential for a model's vendor with this driver class, or undefined. The
model's Active vendor rows are tried in selection order, so the answer is the credential of the
row that selection would pick for that driver class.
The MJ: AI Models row id.
The vendor's DriverClass.
A key resolver for one model: its platform credential first, then fallback (the run's keys,
then the environment, as the caller built them).
The MJ: AI Models row id the resolver serves.
The resolver consulted when no platform credential applies.
The platform credentials resolved for a set of realtime models, keyed by
MJ: AI Model Vendorsrow. Immutable; answers synchronously.