nx_inter_layer_coherence.nx

nx_inter_layer_coherence.nx -- cross-layer constraint checker. Per honest audit 2026-05-16: per-layer graders can each be S-class while the OVERALL composition is nonsense -- river flowing uphill, forest in a desert biome, town built on a cliff edge, castle in a swamp. This primitive grades the INTER-LAYER CONSTRAINTS that must hold for a coherent world. Four constraints scored individually + composed: 1. RIVER_DRAINAGE: rivers should flow downhill. For each polyline segment, sample heightmap at both endpoints; score = fraction of segments where h_end < h_start. 2. FOREST_BIOME_MATCH: forests should sit in biomes that support forests (BOREAL_FOREST / TEMPERATE_FOREST / TROPICAL_RAINFOREST or GRASSLAND). Score = fraction of forest positions in valid biomes. 3. TOWN_FLATNESS: towns should be on relatively flat ground. Sample local heightmap stddev within town radius; score = inverse of normalised stddev. 4. CASTLE_DEFENSIVE: castles benefit from elevation advantage. Score = fraction of castles whose centre elevation exceeds the mean elevation in a surrounding band of 2x radius. Each function returns Q14 [0, Q]; nx_inter_layer_coherence_grade composes them into a LAYER_VERDICT (kind = NX_LAYER_KIND_READABILITY, refine = NX_LAYER_REFINE_FIX_COHERENCE). genealogy_id: world_design_coherence_canon + leopold_wolman_1957_drainage + medieval_settlement_geography_canon lineage_id: nx_inter_layer_coherence_4axis_v1