Information Geometry and the Master Action of the Directional Vacuum: A Covariant Transport Law for Null-Directional Kinematics

A central open problem in null-directional kinematics (NDK) is the dynamical law governing the transport of the local directional ensemble. In previous work, the informational vacuum was characterized thermodynamically by a normalized probability density $P(\hat{k};x)$ on the local celestial sphere, and gravitational structure was associated with the entropy and anisotropy of this ensemble. The missing ingredient is a covariant kinetic principle for the flow of $P$ from point to point in spacetime. In this paper, that transport sector is constructed using information geometry. Because $P$ is a probability density rather than an ordinary scalar field, the natural local quadratic cost of variation is not $(\nabla P)^2$ but the Fisher-information density $(\nabla P)^2/P$. Promoting this object to the sphere bundle over spacetime yields a minimal covariant action containing spacetime transport, angular regularity, and directional entropy. Writing $P=\psi^2$ converts the Fisher sector into a standard quadratic amplitude form, so the amplitude variable $\psi$ emerges as a natural transport coordinate of the informational vacuum rather than as an independent postulate. The resulting master action couples Einstein--Hilbert curvature, directional entropy, Fisher transport, and a placeholder effective low-energy matter sector into one unified functional. Variation gives a nonlinear field equation on the sphere bundle together with a modified Einstein equation sourced by the directional substrate. The framework does not yet constitute a finished theory of everything, but it provides a precise action principle for the microscopic dynamics of the informational vacuum and a concrete bridge between macroscopic gravity and quantum-like probability transport.