Paper T18: Collapse Mechanics from Coherence Selection A Structural Resolution of Measurement in Holosphere Theory

This paper presents a deterministic, mechanism-level account of quantum measurement within Holosphere Theory. Measurement “collapse” is modeled as structural acceptance dynamics in a discrete angular lattice, not as a stochastic postulate or observer-dependent intervention. When multiple coherence candidates are initiated, they compete for continuation under local admissibility constraints set by finite strain budgets, literal triadic spin closure on three independent axes, and corridor-legal defect transport. Candidates that violate these constraints fail deterministically, while the surviving continuation locks in through closure-compatible amplification at the interface. Apparent probabilities arise from unresolved interface microstate (memory, defects, and strain geometry), not intrinsic randomness. The paper formalizes shared-budget admissibility, defines a governance-grade Metastable Acceptance Window (MAW) KPI to capture near-threshold competition, and validates the mechanism via a declared parameter sweep. The framework reproduces outcome uniqueness, effective irreversibility, and amplification without ontological branching, observer specialness, or added noise terms, and it yields falsifiable predictions linking measurement statistics to interface structure and preparation history.