feat: Add new Geometry Nodes groups for image relief and shadeless shader

- Implemented the "O Image Relief Plane" Geometry Nodes group to create a fixed-base image relief using depth images and various parameters.
- Created the "O Shadeless" shader node group to display color without scene lighting while preserving shadows and reflections.
- Introduced a preview feature for node groups, allowing for interactive visualization of node arrangements in an HTML format.
- Added a template HTML file for rendering node previews with customizable views and controls.

tests/test_depth_surface_split.py

@@ -12,9 +12,8 @@ ROOT = Path(__file__).parents[1]
 
 sys.path.insert(0, str(ROOT / "src"))
 
-sys.path.insert(0, str(ROOT / "tools" / "node_assets"))
 
-from cutout import build_cutout_group
+from node_asset_test_support import CUTOUT_BUILDERS
 from depth_surface_test_support import assert_closed, component_count, evaluated, surface
 
 
@@ -114,7 +113,7 @@ def test_split_topology_uses_depth_before_display_scaling(depth_scale):
 @pytest.mark.parametrize("shape", ["SOLID", "DEPTH_SOLID", "DEPTH_BALLOON"])
 def test_each_asset_cleans_the_original_geometry_before_shaping(shape):
     bpy.ops.wm.read_factory_settings(use_empty=True)
-    group = build_cutout_group(shape)
+    group = CUTOUT_BUILDERS[shape]()
     links = [link for link in group.links if link.from_node.bl_idname == "NodeGroupInput" and link.from_socket.name == "Geometry"]
     assert len(links) == 1
     assert links[0].to_node.bl_idname == "GeometryNodeDeleteGeometry"