Terminal Codebook and L5 Partner-Identity Classifier in a Computational Longevity Discovery Pipeline (Trinity Milestone, Claims #50-#54, 2026-03-18)

This milestone package fixes a coherent computational terminal-architecture block from the Trinity longevity discovery pipeline. Claims #50-#54 establish a unique minimal corridor code, a unique minimal late-state code, an orthogonal terminal codebook, the failure of a disjoint pair partition under common pair projection, and an L5 partner-identity classifier in which L3 yields shared rescue while L2 and L4 remain late-only.