Validate a candidate result returned under the a2a2p domain-solutioning contract. The exact output of prepare_domain_solutioning_case is a prerequisite; malformed or non-prepared cases return a versioned machine-readable recovery workflow without weakening case-shape or digest checks. The operation verifies the source-case digest and provenance shape, rejects authority promotion and intent or design-file mutation, re-screens every candidate at quote stage, and runs the deterministic engineering review only after screening allows it. A successful response content-addresses the exact candidate result and returns a copy-ready, non-automatic source binding for prepare_simulation_study; every objective, constraint, physical input, setting, and validation plan remains caller-supplied. It stores nothing, runs no solver, calls no model or supplier, applies no patch, and grants no provider, quote, order, payment, or fabrication authority.