Title: The Symmetric Layered Model (SLM): A Mechanical Foundation for Unified Physics Author: Dennis Zetting Publication Date: February 14, 2026 (6:52pm EST) License: Creative Commons Attribution 4.0 International (CC BY 4.0) Abstract / Description: This manuscript establishes the fundamental priority for the Symmetric Layered Model (SLM), a dual-layered manifold theory that replaces probabilistic field abstractions with a structural mechanical metric. Key Intellectual Priority Claims: Mass-Resonance Identity: The explicit derivation of the electron rest mass ($0.511$ MeV) as the fundamental ground-state eigenfrequency of an inter-sector vacuum tether. The Stueckelberg Portal Scale: The identification of the 145 MeV energy scale as the stabilizing mechanical stiffness ($\kappa$) of the vacuum manifold and the primary mediator of the Muon $g-2$ anomaly. Phase-Cancellation Mechanism: The resolution of the Cosmological Constant problem ($10^{120}$ error) via structural destructive interference between antipodal $Z_2$ symmetric sectors. Metric Gravity ($G \propto 1/T$): The definition of the Gravitational Constant as the emergent inverse modulus of universal vacuum tension. Predictive Milestones: Specific, falsifiable predictions for the Belle II 145 MeV dark photon peak, the COSI boxy 511 keV morphology, and the X17 (17 MeV) first-harmonic vibration. Copyright Notice: © 2026 Dennis Zetting. All rights reserved. The mathematical relationships between the $145$ MeV Stueckelberg portal and the $0.511$ MeV lepton resonance described herein are the original intellectual property of the author. This document serves as a formal timestamp of discovery prior to the release of 2026 empirical datasets from Belle II and NASA/COSI.