CDIP v2.0 Route-B Digital τ -Realization Declaration for G-τ .4

This article formalizes a digital realization of the imaginary-time operator Pτ0 used in the PERIMETER_AUX gate G-τ .4 (Ghost-State Legitimacy), thereby removing the “timebase manipulation” attack class when Pτ0 is implemented as a deterministic numerical operator. The document preserves a physical realization note as a non-binding specification path, with strict non-interference (NI) against CDIP v2.0 CORE. The outcome is an auditable, earliest-failure-complete, and reproducible policy surface for FULL_CDIP_STACK (v2.0 CORE + OPA 2.0 + G-τ .4).