Paper 19: Classical Derivation of Light Cones and Emergent Causality in Holosphere Theory

This paper derives light-cone-like causal structure in Holosphere Theory from admissibility-limited angular coherence transport, rather than treating spacetime causality as a primitive postulate. Using deterministic thresholding on cumulative angular misalignment (δφ) and finite-speed coherence propagation, we model causal reach as an expanding coherence shell with radius R(t)=vφt. We then show how adding curvature flow terms (D∇²δφ) converts sharp decoherence fronts into deformable causal membranes, yielding measurable diagnostics such as shell thickness and eccentricity under anisotropic strain. Proxy 2D and 3D simulations demonstrate tension horizons, layered time behavior via entropy-clock divergence, and threshold-triggered loss of correlation-supporting connectivity. The results support a permissibility framing of causality: influences become causally effective only insofar as they remain transmissible and recordable under corridor admissibility constraints, consistent with the governed attribution framework developed in Paper 119. The paper concludes with decision-grade implications for causal limits, directional decoherence, and curvature-regulated horizons within a unified coherence lattice.