Stage-resolved tracking benchmark public materials

Public companion materials supporting the manuscript 'Stage-resolved bottlenecks from track finding to fitting in layered detectors'. This restricted public package includes aggregate result tables, sanitized Stage-II summaries, final PDF figure assets, documentation, and public-safe verification scripts. It does not redistribute the original benchmark generator, canonical SiHits_3D dataset, derived working copies, near-window data, per-track diagnostic exports, or trained model weights because permission for public redistribution has not yet been confirmed.