Deterministic governed GEPA roundtrip proof with mock model profiles, candidate evaluation, comparison, promotion gates, rollback refs, and trace refs.
The proof path uses GEPAFramework plus GEPA.MezzanineOptimizerAdapter
through Mezzanine.OptimizationEngine.propose_candidates/3, then projects the
candidate through AppKit.OptimizationSurface. gepa_buildout is not required
for this canary.