Departure From the Photon Baseline: Paper 12 — The Aggregated Ledger: Many-Body Statistical Mechanics and the Emergence of Bulk Thermodynamics

This upload contains Paper 12 of the series Departure From the Photon Baseline: A Universal Ruler for Mass, Gravity, and Time, titled "The Aggregated Ledger: Many-Body Statistical Mechanics and the Emergence of Bulk Thermodynamics" (v4, 2026). This foundational work constructs many-body statistical mechanics within a single-regime, discrete ledger framework without importing continuum calculus, ensembles, or sampling-measure postulates. Key contributions include an exact combinatorial counting rule yielding a population census, a proven aggregate tick operator, the dissolution of the sampling-measure postulate, the relational construction of capability, bulk temperature as an exact rational reconcile density, an ensemble-free thermal arrow, and a rigorous two-level molecule reduction. The document includes a full machine-checked verification suite and explicit falsification conditions.