Reproducibility code for surrogate-accelerated inverse reconstruction and local Newton--Kantorovich verification

Reproducibility scripts, source-code audit materials, numerical validation code, high-precision crosschecks, and recorded logs associated with a study of surrogate-accelerated inverse reconstruction and local Newton--Kantorovich verification. The FastDA portion audits literal source-code statements at a pinned public commit and reproduces a window count and conditioning benchmark; it does not rerun FastDA training or DNS. The numerical verification portion examines one discrete nonlinear boundary-value inverse problem and one parameter case. The local certificate computation is accompanied by independent numerical crosschecks, but is not a global, continuous-PDE, or FastDA/DNS guarantee.