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_node_assets.py

@@ -1,5 +1,4 @@
 import unittest
-import sys
 from pathlib import Path
 
 
@@ -8,11 +7,11 @@ SOURCE_ROOT = PROJECT_ROOT / "src" / "anyimage"
 
 
 class NodeAssetsTest(unittest.TestCase):
-    def test_geometry_assets_pass_layout_overlap_checks(self):
+    def test_geometry_assets_preserve_node_structure(self):
         import bpy
 
-        sys.path.insert(0, str(PROJECT_ROOT / "tools" / "node_assets"))
-        from node_layout import validate_node_layout
+        from node_asset_test_support import validate_node_structure
+        from tools.nodes.arrangement.arrange import arrange_nodes
 
         bpy.ops.wm.read_factory_settings(use_empty=True)
         with bpy.data.libraries.load(
@@ -24,9 +23,15 @@ class NodeAssetsTest(unittest.TestCase):
             for group in target.node_groups
             if group.bl_idname == "GeometryNodeTree"
         ]
-        self.assertEqual(len(groups), 5)
+        self.assertEqual(len(groups), 6)
         for group in groups:
-            validate_node_layout(group)
+            validate_node_structure(group)
+            positions = {node.name: tuple(node.location) for node in group.nodes
+                         if node.bl_idname not in {"NodeReroute", "NodeGroupInput"}}
+            arrange_nodes(group)
+            for name, position in positions.items():
+                for actual, expected in zip(group.nodes[name].location, position):
+                    self.assertAlmostEqual(actual, expected, delta=0.01, msg=f"{group.name}: {name}")
 
     def test_production_code_does_not_create_node_groups(self):
         offenders = []