024-second-local-semantic-backend

Second local semantic backend (deferred)

Reserves backlog item RUSTEV-012 and the architecture's increment 3 "second semantic backend": a second local, offline `DecisionBackend` added only after the first local backend (spec 011) is complete and comparable evaluation reports show a concrete need it would answer. It declares its actual capabilities, artifact identity, resource use and numerical behavior, and must be swappable with spec 011's backend and the Jev adapter without any authority-path or core contract change. Claims no code, names no model, and adds no dependency.