The Equivalence Principle Versus a Spin-Coupled Frame: Predicted Violations for Unpolarised and Polarised Test Bodies in Einstein-Cartan Gravity

In Einstein-Cartan gravity, torsion is fixed algebraically by the spin density of matter and does not propagate. A test body whose spins are unpolarised therefore feels no torsion force at leading order: the mean spin density vanishes, and outside a source body there is no torsion field to couple to in any case. This paper computes, channel by channel, the residual equivalence-principle violation that survives that cancellation in the frame defined by the Aldred Limit, rho_A = 9.72e54 g/cm^3. The surviving term for unpolarised matter is the incoherent spin self-energy, with the material fraction computed from the measured isotope abundances, nuclear spins, and unpaired-electron counts of each test material. Predicted Eotvos parameters: eta(Be,Ti) = 1.05e-56 for torsion balances (published bound scale 1.8e-13; margin 43.2 orders of magnitude), eta(Ti,Pt) = 9.51e-58 for the MICROSCOPE pair (bound scale 2.7e-15; margin 42.5 orders), and eta(Earth,Moon) = 2.08e-59 for lunar laser ranging (bound scale 1.4e-13; margin 45.8 orders). Composition-blind upper bounds remain 39-42 orders below the published bounds. Residual coherent polarisation of unpolarised bodies contributes fractions below 1e-76. For polarised bodies, a separated polarised source and polarised test body exchange no signal at all in this frame: the predicted spin-spin interaction is exactly zero at every separation. The one nonzero polarised channel is the test body's own spin self-energy: 2.78e-59 for a realistic electron-polarised material (SmCo5 class) and 2.21e-54 for the absolute ceiling of a fully nuclear-polarised platinum-density body, which still falls short of MICROSCOPE-class sensitivity by 39.1 orders of magnitude. AI-use disclosure: this work was prepared with the assistance of Dave, an artificial intelligence system built and operated by Aldred Industries. The computations were performed by a saved, deposited script; the author reviewed the results and takes responsibility for the contents.