GR–QC Bridge via Spacetime Safety Equation: Multi-channel Verification of Blackfield and Observational Scalar αBF

This preprint defines an observational-layer readout protocol that rescales reported proper time and reported volume measures by a single dimensionless factor, while keeping the underlying dynamics on the base spacetime metric unchanged. The paper formulates the readout as an interface specification for estimator pipelines (reported-time and measure conventions, composability, and uncertainty propagation), so that downstream derivations can consume the same inputs and return comparable reported outputs without modifying equations of motion, causal structure, or conservation laws. Revision notes (v2): the manuscript is refocused into a pure readout-layer prescription and estimator-interface paper. Motivations and wording that could be misread as a dynamical metric modification (e.g., degeneracy or “physical effective metric” interpretations) are removed or explicitly excluded; the role of the rescaling parameter is clarified as a calibration/convention input. The measure and proper-time rescalings are harmonized, terminology is tightened for journal-facing neutrality, and the linkage to subsequent cosmology-facing closed-form derivations is made explicit as an interface (not as a new dynamical model).Related papers (Zenodo DOIs): 10.5281/zenodo.18169180; 10.5281/zenodo.18169038; 10.5281/zenodo.18158333; 10.5281/zenodo.18159247; 10.5281/zenodo.18158453; 10.5281/zenodo.18158537.