Sector Paper XXIV — Geometric Phase‑Rotation and the Structural Origin of Neutrino Oscillation

Neutrino oscillation is the only laboratory‑verified phenomenon that requires physics beyond the Standard Model, yet existing explanations rely on patchwork additions such as arbitrary Yukawa couplings, sterile states, or high‑energy seesaw mechanisms. Sector Paper XXIV introduces a parameter‑minimal geometric phase‑rotation mechanism in which flavour corresponds to geometric alignment modes, oscillation arises from energy‑dependent geometric phase accumulation, and effective mass emerges as a geometric delay rather than a Higgs‑based coupling. Matter‑enhanced oscillation is reinterpreted as density‑driven geometric modulation consistent with solar, atmospheric, reactor, and accelerator data. This public‑safe formulation integrates with the global rotation‑geometry chain established in Sectors I–III and XIX–XXIII, providing the geometric analogue of the internal neutrino machinery of Sector M. The result is a structurally coherent, non‑perturbative, and falsifiable framework that replaces patchwork mass insertions with a unified geometric origin for flavour, oscillation, and matter‑dependent modulation.