Thermodynamic Constraints on Measurement Events: A Boundary Framework for Classical Information

We develop a thermodynamic framework for quantum measurement and black hole information. The framework rests on three results: (1) a conditional record-formation heat bound with a three-stage measurement taxonomy and explicit operational conditions, validated by a differential microcalorimetry protocol and Lindblad master equation simulation; (2) a proof that the Born rule P = |psi|^2 is the unique phase-independent probability rule consistent with L^2 normalization, using one thermodynamic axiom and three structural axioms; and (3) the exact Schwarzschild identity T_H S_BH = (1/2)Mc^2 (Smarr relation) and a complete information and energy accounting framework where measurement creates classical information and black holes render classical records operationally inaccessible to exterior observers, verified dynamically across the full evaporation trajectory and the Kerr-Newman parameter space. Falsifiable predictions include measurement calorimetry and Hawking-Landauer verification.