X-State Field Theory (XSFT), Version 4: Consistency tests and controlled collapse of geometric candidates

Version 4 of X-State Field Theory (XSFT) reassesses the X-state hypothesis: whether gravitational compression can produce a sustained, nonsingular geometric configuration capable of preserving quantum information. It explicitly revises the evidential status of Version 3 (DOI: 10.5281/zenodo.19695141), rather than retaining its unverified observational claims as established predictions. The principal numerical study concerns spherically symmetric dust collapse in metric f(R) gravity with f(R) = R + aR². Three nested grids provide evidence of approximately second-order self-convergence of monitored fields and curvature invariants at t/L = 2.06, with decreasing Hamiltonian and momentum constraint residuals, including the center. Proper-time diagnostics show continued central contraction and positive timelike Ricci focusing. These results concern a finite resolved interval; they do not establish a regular black-hole core, singularity resolution, or global dynamical stability. The supplementary research record examines scalar–Gauss–Bonnet spontaneous scalarization, weakly nonlinear metric backreaction, restricted de Sitter core tests, quantum channels and quantum error correction, horizon geometry and signature change, relational time, presymplectic boundary states, a Chern–Simons boundary candidate, bulk–boundary gluing, a graph-level Dirac constraint analysis, and restricted local geometric no-go results. The candidate models and their assumptions are distinguished; no reversible black-hole information capture-and-release mechanism is established. The accompanying research package contains code, archived numerical data, editable manuscript sources, historical reports, and checksum manifests. Limitations, unsuccessful numerical formulations, and unperformed tests are documented. Substantive AI assistance is disclosed. This is a research preprint, not a peer-reviewed journal publication.