PRE-GHR XXIV: The Interface Protocol — Why Gear Governance Does Not Require Predicting the Future

The PRE-GHR Gear system is a discrete, linear control architecture governing a continuous, nonlinear, emergent technical evolution. This paper addresses the meta-legitimacy question: how can a discrete governance framework claim authority over a process it cannot predict? We argue that the Gear system governs not technology directly, but the interface between technology and society — the lock-in points where technical capability produces social consequence. --- v5 changelog --- (1) Theorem 4.1 → Proposition 4.1: downgraded from proof to justification; completeness positioned as engineering objective, not mathematical guarantee. (2) Theorem 5.1 → Proposition 5.1: convergence argument strengthened with residual gap delta > 0 and contingent clause on generation rate vs absorption capacity, aligning with Paper I/XXX delta_0 theorem. (3) Caveats 4-B and 4-C merged into unified Caveat 5 (External dependency and the self-legitimation boundary): operator dependency + consistency does not equal correctness. (4) Date frozen: July 25 (v4) -> July 29 (v5).