Read External Source Scaffold production audit preview metadata

Owner/admin metadata for the External Source Scaffold production hardening audit preview route. Returns accepted input shapes, supported workstreams, and a forced-false production release/smoke authority boundary. It performs no DB writes, implementation execution, production release, production smoke execution, route mutation, public discovery mutation, Seller OS mutation, trust/ranking mutation, x402/wallet/settlement mutation, provider dispatch, browser automation, memory write/promotion, live finance action, or private Full ECF exposure.