ARCHIVAL VERSION — [Alpha Locking v6: Finite-Resolution Termination and the Structural Fixing of the Fine-Structure Constant]

Important update: This is an earlier Alpha Locking record in the development path toward the current FDC/SCR structural readout framework. For the current compact structural readout record, including the updated readout near Φ_G ≈ 137.035999166, to be compared externally with CODATA 2022 α⁻¹ = 137.035999177, please see: SCR-v4: Structural Constant Readouts DOI: 10.5281/zenodo.20069325 For the current formal framework behind the readout grammar, please see: FDC-v7: Finite Distinguishability Closure DOI: 10.5281/zenodo.18926335 This earlier Alpha Locking record is retained as an archival development record. The current preferred references are SCR-v4 for numerical readouts and FDC-v7 for the formal closure framework. --------------------------------------------------------------------------------------------------------------------------------------- This record contains the main paper, the audit supplement, and the reference implementation for Alpha Locking v6. Alpha Locking v6 establishes that a finite-resolution update structure cannot terminate at an arbitrary depth. Under purely discrete, non-optimizing accept/reject predicates, the update depth is forced to terminate at a unique minimal admissible value, leaving a residual dimensionless constant. No fitting, tuning, optimization, or empirical input is used.The fine-structure constant appears solely as a structural residue of finite-resolution termination. The Supplement specifies a complete audit procedure.The attached Python code performs a finite, explicit enumeration and verifies the singleton admissible depth condition. This work completes the one-way trilogy:MOF v3 → PFC v4 → Alpha Locking v6.