Unified Dark-Sector Predictions from Grand Consistency Theory

This paper develops a unified numerical framework for testing the astrophysical dark-sector predictions of Grand Consistency Theory (GCT) across galaxies, galaxy clusters, halo populations, and cosmic voids. The central test is whether a single universal GCT gravitational parameter set can reproduce phenomena conventionally attributed to dark matter without sector-specific retuning of fundamental gravitational parameters. The analysis includes galaxy rotation curves, radial acceleration and scaling relations, cluster dynamics and gravitational lensing, halo-equivalent structure and abundance, and void density, size, velocity, and weak-lensing observables. These predictions are incorporated into a covariance-aware statistical framework that separates universal theoretical parameters from system-specific astrophysical inputs, calibration quantities, observational nuisance parameters, and numerical uncertainties. Cross-scale consistency, dynamical-lensing agreement, parameter economy, and out-of-sample prediction provide the principal criteria for assessing the theory. The resulting framework establishes a quantitative and falsifiable test of whether one GCT gravitational realization can account consistently for dark-sector phenomenology across both overdense and underdense astrophysical environments.