Add comprehensive tests for cutout and mesh functionalities

- Introduced `test_cutout.py` to validate cutout pie menu behavior, image lasso options, and mesh detail calculations.
- Added `test_mesh.py` to ensure correct tangent normal rasterization, plane source topology, and depth surface evaluations.
- Created `test_mesh_blender.py` to verify material node groups, tangent baking, and local cutout building from Blender images.
- Implemented tests for handling alpha regions and ensuring geometry nodes maintain expected behavior.

tools/validate_depth_plane_asset.py

@@ -285,14 +285,37 @@ def main():
         and node.node_tree == surface_group
     ]
     assert len(surface_group_nodes) == 1
-    assert surface_group_nodes[0].name == "O DA3 Surface Layer"
+    assert surface_group_nodes[0].name == "O Image Layer"
     surface_inputs = [
         item.name
         for item in surface_group.interface.items_tree
         if item.item_type == "SOCKET"
         and item.in_out == "INPUT"
     ]
-    assert surface_inputs == ["Color", "Alpha", "Bump Scale"]
+    assert surface_inputs == [
+        "Color",
+        "Alpha",
+        "Normal",
+        "Normal Scale",
+        "Object Space",
+        "Bump Scale",
+    ]
+    normal_input = next(
+        item
+        for item in surface_group.interface.items_tree
+        if item.item_type == "SOCKET"
+        and item.in_out == "INPUT"
+        and item.name == "Normal"
+    )
+    assert tuple(normal_input.default_value) == (0.5, 0.5, 1.0, 1.0)
+    normal_scale = next(
+        item
+        for item in surface_group.interface.items_tree
+        if item.item_type == "SOCKET"
+        and item.in_out == "INPUT"
+        and item.name == "Normal Scale"
+    )
+    assert normal_scale.default_value == 1.0
     surface_outputs = [
         item.name
         for item in surface_group.interface.items_tree