Wildlife and nature: animals, beehives, bushes, flowers, rocks, logs

New stdlib module wildlife.rhai:
- Animals (new palette category): Deer (stag with antlers, does, fawns),
  Wild boar, Fox, Elephant (bull with tusks, cow, calf), Rabbits. Low-poly
  solids from faces (loft, tube), parts drawn back to front by depth, faces
  edged in their own shade (class beast). Herds scatter round a spot, each
  animal its own sprite facing about the object's rotation. Grazing
  animals switch between two head poses (iso-pose2 groups), elephants curl
  their trunks, rabbits hop.
- Birds and Butterflies as flocks: swim() takes a shape (bird, fly, bee);
  wings flap out of step. Fish output unchanged.
- Beehives on stands with supers, lids, entrances and bees flying round;
  Bush (round, flowering, berries); Flowers (bed in rows or meadow); Rocks;
  Log or stump. g-meadow and g-soil ground materials.
- polyline() takes 3D points as documented (antlers).

Theme colours for dark and light, viewer CSS for poses, flapping, hopping.
examples/country: elephants in a paddock with a cut corner, deer at a
forest edge, boar, fox, rabbits, an apiary by a meadow, a pond, a lane,
fence and hedgerow at angles; Country demo in the web Studio and deploy.
MCP guidance, README, SCRIPTING, ROADMAP.

Tests: Rust 78, Studio 122; existing examples draw the same (only the
embedded theme CSS grew).

crates/isokit-project/tests/demo.rs

@@ -72,7 +72,7 @@ fn demo_passes_the_check() {
     assert!(f.is_empty(), "{f:?}");
 }
 
-/// The house, factory and streets demos: every view draws every object without warnings
+/// The house, factory, streets and country demos: every view draws every object without warnings
 /// or depth-sort cycles (walls and belts must not overlap), and the projects pass the check.
 #[test]
 fn house_demo_renders_every_view_cleanly() {
@@ -89,6 +89,11 @@ fn streets_demo_renders_every_view_cleanly() {
     example_renders_every_view_cleanly("streets");
 }
 
+#[test]
+fn country_demo_renders_every_view_cleanly() {
+    example_renders_every_view_cleanly("country");
+}
+
 fn example_renders_every_view_cleanly(name: &str) {
     let p = Project::load(
         Path::new(env!("CARGO_MANIFEST_DIR"))