Add Ground Zero environment asset variation

Docs/Terrain/GroundZeroFoliagePass.md

@@ -39,3 +39,7 @@ current prototype geometry now uses dedicated Ground Zero tree, shrub, and dry
 grass materials. The next biome/resource passes should replace prototype meshes
 with real coastal California scrub, grassland, woodland, and resource-specific
 assets, then tie spawn density to land-cover and hydrography data.
+
+The natural environment variation pass adds nearby labeled accent actors for
+additional canopy, trunk, bush, grass mat, rock, and water silhouettes so the
+demo no longer depends only on one repeated foliage mesh per family.

Docs/Terrain/GroundZeroNaturalEnvironmentPass.md

@@ -11,6 +11,9 @@ space.
   tree, shrub, and dry grass materials.
 - Wood, fiber, stone, and freshwater actors receive distinct first-pass
   materials.
+- First-pass asset variation actors add additional tree canopies/trunks, rounded
+  bushes, grass mats, rock slabs, and a visible freshwater surface with varied
+  meshes, scales, rotations, and material families.
 - The setup remains repeatable through `Scripts/setup_ground_zero_demo_map.py`.
 
 ## Material Assets
@@ -29,11 +32,14 @@ space.
 `Scripts/verify_ground_zero_natural_environment_pass.py` checks that the
 materials exist, the landscape uses the terrain material, the foliage actor has
 the expected instance counts and material assignments, and resource/water actors
-are visually dressed.
+are visually dressed. It also checks the first-pass asset variation layer:
+eleven labeled variation actors, at least four mesh silhouettes, unique scale
+profiles, and coverage across tree, bush, grass, rock, and water visual
+families.
 
 ## Follow-Up
 
 This pass deliberately keeps the current prototype geometry so it stays small
-and stable. The next environment work should add first-pass asset variation so
-trees, bushes, grass, resource nodes, and water no longer read as repeated
-placeholder shapes.
+and stable. Later environment work should replace these prototype silhouettes
+with region-appropriate sourced or custom meshes, then drive density and shape
+selection from land-cover, slope, hydrography, and biome data.