Topological Origin of Nuclear Forces: Deriving SU(2) and SU(3) Gauge Symmetries from Lattice Geometry

Following the unification of Gravity and Electromagnetism in Parts I-III, this paper extends the Excitation Field Unification (EMU) framework to the nuclear domain. We propose that the gauge symmetries of the Standard Model are not abstract internal spaces, but direct consequences of the 3D spatial lattice geometry. We identify **Color Charge (SU(3))** with the state space of axis-locked defects, explaining confinement as a geometric constraint. We identify **Weak Isospin (SU(2))** with the chiral helicity of topological defects, explaining parity violation as a structural asymmetry. This completes the geometric interpretation of the Standard Model group U (1) × SU (2) × SU (3).