Rotor Transport on Multiply Connected Domains: Covering-Space Constraints in Spin Dynamics

Quantized observables are usually attributed to quantum mechanics. We argue their origin is topological. Integer quantum numbers arise wherever transport around a nontrivial loop requires equivalence after projection in the associated phase bundle. Using Spacetime Algebra, we show that the rotor closure condition R_γ = ±1 provides a common covering-space criterion for integrality in atomic orbitals, superconducting rings, and black hole photon rings, spanning 23 orders of magnitude. Dynamics sets the characteristic scale. Topology enforces integrality. This is the second paper in a series examining scale-independent consequences of covering-space constraints on conserved currents. Version history v1 (February 2026): Initial publication as "Holonomic Closure as the Geometric Origin of Quantization Across Scales." v2 (February 2026): Title revised to reflect rotor transport and covering-space framework. Lift/projection language standardized throughout for consistency with series. SU(2)→SO(3) double cover explicitly named. No changes to mathematical content or results.