On the Regime-Limited Validity of Quantum Mechanics (IM-I002, v0.3)

This document is part of the Informational Mechanics (IM) framework and is published in the IM-I (Reviews & Syntheses) series within the IM v0.3 corpus. The paper synthesizes recent IM work on universality and regime-limited validity to clarify the status of quantum mechanics under admissibility constraints. Rather than proposing modifications to quantum theory, it analyzes the conditions under which claims of global validity remain scientifically meaningful. Drawing on IM-C003 (regime-limited universality), IM-E001 (operator criteria for universality), and IM-D005 (structural non-derivability across regime transitions), the document shows how quantum-mechanical unitarity and state evolution must be understood as regime-bound statements whose validity depends on operator-defined implementability and cross-regime comparability. The paper introduces no new axioms, models, or empirical results. Its purpose is clarificatory and integrative: to provide a coherent account of how quantum mechanics retains full validity within admissible regimes while avoiding unwarranted global extrapolation beyond operator-defined structure.