Prove it

"Prove the model was right", "did the model call it", "show the track record", "audit these decisions", "did the retention offers work" - use when someone needs to show that Datagoat's answers were right, or that acting on them worked. Covers dg_backtest (day 0: what a record dg_map built from a log supported in its own past, cutoff by cutoff, against a naive rule), verifying Verdicts (with dg_verify or offline, with no call to Datagoat), keeping each signed call from before the outcome, grading calls against what happened in a walk-forward replay, recording actions with dg_attest and outcomes with dg_report_outcomes, reading dg_track_record (the model's calls against rep…