The Continuous Elastic Cosserat Medium: A Unified Field Theory of Matter, Forces, and Spacetime (White Paper)

We present a unified field theory based on two postulates: (1) the universe consists of a continuous elastic Cosserat medium, (2) all physical processes obey the principle of least action. From these postulates alone, we derive: - The finite speed of light and Lorentz symmetry as emergent properties of the medium's elastic ground state; - Quantum mechanics as the effective dynamics of localized wave packets in the medium; - Protons and neutrons as topological solitons (B=1) of the orientational field; - Electrons as torsion bound states in the frame field; - The four fundamental interactions (strong, electromagnetic, weak, gravitational) as distinct elastic responses of the same medium. The theory contains exactly two free parameters, fixed by the proton mass and charge radius. A 27-point experimental audit shows agreement across single-nucleon statics, excitation spectra, parton distributions, nuclear forces, and fundamental interactions. Three falsifiable predictions are presented: proton scalar polarizability, a torsion-induced spin-spin force, and ultra-high-energy photon dispersion. This white paper provides the complete theoretical framework, experimental status, and open problems.