Environmental Local Expansion in Scalar–Tensor Cosmology: A Controlled Successor to the Cosmic Gradient Energy Model

This preprint presents a controlled scalar–tensor successor analysis to the withdrawn quantitative implementation CGEM v1.3. Three frozen candidates are reconstructed from their actions and audited through local screening, cosmological background evolution, linear perturbations, and a Jordan-frame environmental local-expansion diagnostic. Candidate A2 provides one reproducible same-parameter realization with late-time scalar-driven acceleration, local Cassini compatibility, and a specified candidate-versus-GR residual in a finite Fourier window. Candidate A1 remains blocked by unavailable experiment-identical local geometry. Candidate B retains supported local screening but its homogeneous cosmological symmetry-breaking trajectory remains unresolved. The local expansion scalar is not identified with an observationally fitted Hubble constant, and detectability is not claimed. The exact checksum-frozen evidence archive and its per-file SHA-256 manifest are included in this deposit. CGEM v1.3 remains preserved in the version history as a withdrawn quantitative implementation; its discarded equations and phenomenological claims are not reused.