nx_forest_layout.nx

nx_forest_layout.nx -- specialized forest generator (NOT FBM noise). First demonstration of the kind-specific-generator cardinal `feedback-kind-specific-generators-not-broad-noise`. Forests have INTERNAL LOGIC -- species distribution by biome, age affecting canopy size, clearings, edge effects -- none of which is FBM noise. This primitive ships that logic. Per user 2026-05-15: "what houdini is doing or blender where you have nodes that are tiny gens of their own... right now our minecraft clone has no sense of these things... forest rivers wind erosion water erosion beaches gradients weather hammered lush etc all shouldnt be broad stroked." Forest-internal logic in v1: - Hash-deterministic tree positions inside a region (per-tree x, y from seed). V2 will compose nx_poisson_disk for guaranteed spacing. - Species hash from a per-biome species set (cold biomes get pine/spruce/dead; temperate get oak/birch/maple; tropical get palm + jungle species). - Per-tree height correlated with species (pine tall + thin, oak short + wide, dead-winter skeletal). - Canopy radius correlated with height + age. - Per-voxel material query: WOOD inside trunk cylinder, LEAVES inside canopy sphere (above 60% of tree height). FULL CAPABILITY (per feedback-maximum-capability-no-simplification cardinal, 2026-05-16): - Poisson-disk tree spacing: nx_forest_layout_generate_poisson enforces minimum inter-tree distance via greedy rejection sampling. Honest fallback when budget exhausted. - Clearing detection: callers pass a list of clearing centres (cx, cy, radius); trees within any clearing are rejected at placement time (anti-poisson meadow zones). - Edge effects: radial density falloff via hash-rejection scaling with distance to region centre (edge cells are sparser than centre cells). - Understory predicate: nx_forest_understory_at returns BUSH / FERN / AIR for non-trunk cells in the tree zone (modelled as