Polarization-Invariant Hidden Time, OS/GNS → CPTP, Strong Positivity, Born Rule, and No Third-Order Interference: In 7D 2t PLI Grand Unification Model

This is a supplemental paper to my paper "Quantum Mechanics from a new Principal of Least Information in conjunction with a secondary time dimension".  It is also a foundation of my 7 Dimension 2t PLI Grand Unification Model.

The program seeks to derive the standard kinematical and statistical structure of quantum
 mechanics (complex Hilbert space, CPTP dynamics, Born statistics, no third-order interference)
 from two inputs: (i) an auxiliary time axis whose Euclideanised influence is reflection-positive,
 and (ii) a Principle of Least Information (PLI) which selects the simplest laws and boundary
 data in the Kolmogorov/MDL sense. Conceptually, no axis in the hidden-time plane (t,τ)
 is ontically preferred; the operational time is a polarization choice that minimises description
 length.