Singularity Avoidance and Zero-Point Motion as Guarantees of Spacetime Extremes: The Blackfield Theory as a Unified Substrate

Preprint. Publicly released on Zenodo prior to journal submission.This paper introduces the Spacetime Safety Equation and develops the Blackfield framework as a minimal sub-observational structure ensuring causal consistency under finite time resolution.It provides a unified substrate for (i) singularity avoidance and (ii) a geometric origin of zero-point motion through an observational-layer minimal update, without adding new dynamical degrees of freedom.Related preprints: doi:10.5281/zenodo.18158248; doi:10.5281/zenodo.18158334.Version v2: minor text edits; references updated with DOIs.