Vacuum Topology and the Origin of Action. A Geometric Foundation for Matter.

We present a geometric framework in which the quantum of action arises as a contour invariant of electromagnetic circulation in vacuum. The vacuum is treated as a physical medium characterized by electric permittivity and magnetic permeability, admitting smooth toroidal configurations as minimal carriers of closed phase circulation. Minkowski spacetime is reinterpreted as the linear regime of this medium. This article establishes the foundational structure upon which subsequent developments—Riemannian deformation, Dirac dynamics, proton topology, and the mass gap—are built.