Boundary Cosmology V2: A Covariant Effective Theory of Finite-Memory Curvature, Boundary Response, Maximum Packing, and Domain Mergers

Boundary Cosmology is an effective gravitational framework in which spacetime curvature is treated as finite, history-dependent, and boundary-conditioned. Physical infinities and exact zeros are not realized in nature. Curvature, density, and information are therefore bounded by maximum-packing limits. The observable universe is interpreted as a descendant of a cascade of merged curvature domains. The theory introduces a boundary-memory tensor, a boundary contrast variable C = DeltaK/Kc, a saturated response alpha(C) = C/(1+C), and a relaxation parameter beta = alpha*tau. In the weak-field limit the effective source is rho_eff = rho - beta*D*rho. The primary strong-field prediction is small, structured, population-correlated non-Kerr residuals in compact-object ringdowns. The primary weak-field prediction is a structured, environmentally correlated boundary-contrast field reconstructed from galaxy rotation curves. One boundary-derived response law must jointly satisfy ringdowns, galaxy rotation curves, cluster lensing, structure growth, CMB constraints, and Solar System recovery.