CDN-370: The 3D Tidal Tensor Lift

CDN-370 lifts the domain-patterned two-body contrast model into full 3D trace-free gravity. Using exact differential acceleration from external point nodes and comparing it to the 3D Newtonian tidal tensor, this artifact tests whether the tensor-class domain memory found in CDN-369 was only a planar projection effect. The result shows that the harsh 2D planar-ring behavior relaxes in 3D, but scalar tensor-RMS contrast still does not erase domain memory: outcomes retain dependence on trace-free tensor eigenstructure, orientation statistics, and finite-distance corrections. The release includes simulation code, matched 3D tensor sweeps, distance sweeps, trajectory projections, figures, prediction hashes, and validation notes.