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).

examples/country/isokit.toml

@@ -0,0 +1,29 @@
+# isokit country demo: animals and plants of the countryside, and fences, hedges and a lane at an angle.
+# Open it with `isokit studio examples/country`.
+title = "isokit country"
+note = "A corner of the countryside: elephants in a paddock with a cut corner, deer grazing at the forest edge, wild boar, a fox, rabbits, an apiary by a wildflower meadow, a pond. The lane bends at 45 degrees, the hedgerow runs along it. Tap anything for its numbers. Drag to pan, Ctrl + wheel or pinch to zoom."
+default_level = "site"
+default_rotation = 0
+prelude = []
+theme = []
+
+[[level]]
+id = "site"
+label = "Site"
+title = "Countryside"
+
+[[param]]
+name = "labels"
+type = "bool"
+default = true
+label = "Labels"
+
+[[param]]
+name = "running"
+type = "bool"
+default = true
+label = "Animation"
+
+[build]
+out = "dist/index.html"
+budget = 6000