nucleus-mechanism-vcg vs nucleus-substrate-sdk vs nucleus-substrate-cli

Economic-projection lifter for the Nucleus substrate, specialized to Pigouvian-VCG auctions. Lifts a cleared auction (single-good Vickrey or knapsack-VCG with Clarke-pivot payments) into a Projection::Economic body that the substrate Receipt envelope can carry. Verifier checks well-formedness — every payment is bound to a bid that was actually present.

Demand-side SDK for the Nucleus substrate. Async HTTP `Client` over the hub plus a single `verify_receipt_fully` entry that walks all four projections (Identity, Capability, Flow, Economic) of a Receipt. Composes substrate-core + identity-projection + flow-projection + mechanism-vcg.

Command-line client for the Nucleus substrate. Single binary `nucleus-substrate` driving offline receipt verification (signature + all-projections), live hub fetches, and counter inspection.