Effective High-Curvature Transitions in Gravitational Collapse: A Phenomenological Framework for Nonsingular Black-Hole Interiors

This revised preprint develops a layered phenomenological framework for investigating nonsingular high-curvature transitions in gravitational collapse. Version 1.1 substantially extends the previous version by introducing an explicit analytic reduced bounce benchmark, curvature diagnostics, a clearly defined transition hypersurface, dimensionless parameterization, reproducible numerical calculations, and accompanying code. The reduced benchmark is intentionally distinguished from the full black-hole interior problem. It demonstrates how a specified effective high-density dynamical system can exhibit a finite-density bounce, but it is not presented as a complete solution for a generic astrophysical black-hole interior. The work formulates a general spherically symmetric interior geometry and identifies mathematical requirements for a possible nonsingular transition, including finite areal radius, curvature regularity, matching conditions, low-curvature recovery, and future perturbative analysis. This study does not claim that black holes have been proven to create new universes, nor does it claim a complete fundamental theory of quantum gravity. Its purpose is to provide a mathematically explicit, phenomenological, reproducible, and falsifiable research framework. Version 1.1 adds explicit benchmark calculations and reproducibility materials while preserving a clear distinction between demonstrated mathematical results and unresolved physical questions.