This preprint monograph presents a finite-shell ether framework for interpreting particles, constants, electromagnetic fields, gravitation, and cosmological observables as stable closure structures of an underlying continuous medium. The central thesis is “structure before principles”: physical laws are treated as effective expressions of stable existence, elastic response, Bernoulli exchange, finite propagation speed, and boundary closure. The manuscript develops a local electron-shell closure with three hard internal results: the boundary eigenvalue N₃, the stable finite electron radius R_E=(5/3)ℏ/(m_ec), and the spin-1/2 finite-shell angular-momentum integral. It further provides structured recovery/interface sections for Maxwell electrodynamics, the Dirac equation, Pauli exclusion, and weak-field general relativity. The Dirac equation is recovered as the first-order spinor envelope of a finite ether-vortex shell through boundary force partition, orthogonal velocity channels, Clifford algebra, and a four-component closure space. Maxwell fields are interpreted through ether circulation, pressure-gradient force deficits, four-potential structure, and boundary source-flow. Pauli exclusion is formulated as a second-variation stability condition for identical finite-shell closures. The work also connects the framework to first-principle particle lifetime scaling, background-temperature closure, constant drift, local G reconstruction, g−2, ring-laser sidereal residuals, and hard-BAO cosmological tests. It is intended as a framework preprint and monograph-style synthesis, with detailed numerical analyses provided in companion works.