feat(scene): phone LOD car and clearcoat coachwork on desktop

Phones and the low tier load a decimated grand tourer built by a headless
Blender script (31k to 11k faces, same nodes and materials). Desktop gets
clearcoat paint and a soft halo parented to the tail bar.

scripts/blender/make-lite-car.py

@@ -0,0 +1,63 @@
+"""Builds the phone LOD of the grand tourer. Headless only:
+
+    blender -b --python scripts/blender/make-lite-car.py -- \
+        src/assets/nightdrive-grand-tourer-chromatic.glb \
+        src/assets/nightdrive-grand-tourer-lite.glb
+
+On a phone the car is about 200 px wide and seen from behind, so the wheel
+machining, the tyre treads and the dense trim carry detail nobody can see.
+They are collapsed; the silhouette parts (body, haunches, glass) are kept
+as authored so the car reads the same. Node names and the hierarchy are
+preserved: car.ts finds the wheels, the light bar and the underglow by name.
+"""
+
+import sys
+
+import bpy
+
+source, target = sys.argv[sys.argv.index("--") + 1 :][:2]
+
+# Fraction of faces kept, by node name prefix (after the "evolution-" prefix).
+RATIOS = {
+    "wheel-machining": 0.22,
+    "tires": 0.25,
+    "body-trim": 0.35,
+    "rear-light-bar": 0.4,
+    "car-underglow-source": 0.35,
+}
+
+bpy.ops.wm.read_factory_settings(use_empty=True)
+bpy.ops.import_scene.gltf(filepath=source)
+
+before = after = 0
+for obj in bpy.data.objects:
+    if obj.type != "MESH":
+        continue
+    name = obj.name.removeprefix("evolution-")
+    faces = len(obj.data.polygons)
+    before += faces
+    ratio = next((r for prefix, r in RATIOS.items() if name.startswith(prefix)), None)
+    if ratio is not None and faces > 200:
+        # Meshes can be shared between wheels; give each object its own data.
+        obj.data = obj.data.copy()
+        modifier = obj.modifiers.new("lod", "DECIMATE")
+        modifier.decimate_type = "COLLAPSE"
+        modifier.ratio = ratio
+        modifier.use_collapse_triangulate = True
+        bpy.context.view_layer.objects.active = obj
+        for other in bpy.context.view_layer.objects:
+            other.select_set(other is obj)
+        bpy.ops.object.modifier_apply(modifier=modifier.name)
+    after += len(obj.data.polygons)
+
+bpy.ops.export_scene.gltf(
+    filepath=target,
+    export_format="GLB",
+    export_apply=True,
+    export_yup=True,
+    export_texcoords=False,
+    export_normals=True,
+    export_materials="EXPORT",
+    export_animations=False,
+)
+print(f"LITE faces {before} -> {after}")