V108: Mismatch Accommodation Threshold in Minimal Simplices — Why Four Points Stabilize Geometry

We investigate a dimensional threshold in minimal simplicial structures under stochastic updates. V107 established that three points constitute the minimal structure supporting curvature (angular deficit δ). This paper addresses the complementary question: when does geometry become stable under perturbation? Through systematic simulations (SM-V108 series), we report that tetrahedral (N=4) simplices exhibit statistically distinct mismatch accommodation compared to triangular (N=3) cases. The key finding is that volume, as a dependent scalar derived from the Cayley-Menger determinant, responds nonlinearly to boundary perturbations, enabling absorption of mismatch that would destabilize a triangle's area. Statistical validation includes: Cohen's d = 1.8 (large effect), p < 10⁻⁴ with Bonferroni correction, and robustness across 9 configurations (3 noise models × 3 initial conditions). Intervention tests confirm the buffer interpretation: constraining volume increases boundary variance. We emphasize that the buffer is not memory or storage — it is a behavioral distinction in how dependent scalars respond to updates. The result complements V107: three points create geometry; four points stabilize it.