ECSM Without Curvature: A Finite-Response Medium Spine for Gravity, Electromagnetic Propagation, Matter, Measurement, Atomic Structure, Chemistry, and Thermodynamic Time

This paper consolidates the ECSM reconstruction chain into a non-geometric finite-response medium spine. In the rebuilt formulation, physical metric geometry, spacetime curvature, geodesic motion, metric horizons and singularities are not primitive mechanisms. The primitive content is a coherent medium with finite response, coherence, stress, transport, relaxation, internal orientation, boundary gradients and stable localized response packets. Gravity-like behaviour is formulated through constitutive response burden and stress gradients. Clock shifts arise from reconfiguration burden. Light propagation is corrected by split electromagnetic constitutive response, n^2 = Z_E/Z_B, so a common scalar channel changes impedance and normalization but not propagation. Lorentz contraction is assigned to moving matter-response patterns rather than to space. Matter is represented as stable finite-energy response packets with triadic closure, charge projection and collective two-state orientation. Measurement is represented as detector-basin selection recovering Born weights as overlap measures. Atomic shells, periodicity and bonding are treated as response-degeneracy and closure phenomena. The thermodynamic arrow is formulated as finite-response relaxation with non-negative entropy production. The manuscript consolidates the NG1R-NG19R reconstruction chain into a single publication spine, separates derived results from scaffold claims, and states the empirical boundary: corrected SPARC/KiDS and CMB split-channel raw-data tests remain the decisive validation stage.