Theta Closure in Modal Triplet Theory IV: Conditional Gravity Scaling and Cosmological Cutoff Audit

We extend the Θ-closure program of Modal Triplet Theory (MTT) from the gauge sector into gravity and cosmology using no additional free parameters. Building on the nonabelian overlap normalizations fixed in earlier work, we show that the same Θ uniquely determines the internal geometric volume entering Newton’s constant up to a single irreducible normalization associated with the underlying theory. Gravity therefore cannot be retuned independently once the gauge sector is fixed. We further show that the coherence scale implied by Θ yields a sharp, model-independent cosmological constraint: admissibility of effective four-dimensional descriptions requires curvature scales well below the coherence scale, leading to an upper bound on primordial tensor modes many orders of magnitude below current and foreseeable experimental sensitivity. These results demonstrate that Θ-closure propagates coherently across the Standard Model, gravity, and cosmology at leading order, with explicit falsification criteria and without introducing new sector-specific assumptions.