We propose that "dark matter" is not particles but the geometric response of the D = 3 spatial lattice to baryon stress. The dark matter to baryon ratio Ω_DM/Ω_B = 3√3 ≈ 5.2 is derived from icosahedral geometry: three 11-bridges at 120° phase separation couple baryon oscillations to the lattice, with √3 emerging as the real power factor at the center (the standard result from 3-phase systems). Observed ratio: ~5.4, giving 96% agreement. We derive the MOND acceleration scale from first principles: a₀ = cH₀/(3√3) = 1.26×10⁻¹⁰ m/s² (observed: 1.2×10⁻¹⁰, 95% match). The 1/r "dark matter" term arises from baryon phase coherence propagating through the lattice as wave amplitude, distinct from the 1/r² Newtonian term. We predict: (1) No dark matter particles will ever be detected. (2) Galaxies without dark matter lack spiral structure — confirmed by NGC 1052-DF2 and DF4. (3) Dark matter always traces baryons because it IS the baryon-lattice coupling.