Optimize Cutout Geometry Nodes

- Refactor Depth Cutout to reuse the projected outline field, reducing redundant boundary calculations and improving performance.
- Derive the center field from shared low-frequency fields, eliminating an unnecessary blur operation.
- Implement triangle-only strip cleanup for Depth Cutout, as the input is confirmed to be triangulated.
- Short-circuit zero-thickness branches in both Cutout and Depth Cutout to avoid unnecessary geometry generation.
- Standardize internal attribute naming with a new `_o_` prefix and implement wildcard cleanup for temporary attributes.
- Update relevant tests to ensure functionality remains consistent and validate changes against existing behavior.

tools/nodes/common/cutout_boundary.py

@@ -20,7 +20,7 @@ def remove_boundary_triangles(group, geometry):
     return delete.outputs["Geometry"]
 
 
-def original_boundary_field(group, original):
+def original_boundary_field(group, original, rim=None):
     """Sample the unsplit outline in UV space after projection and separation."""
     nodes, links = group.nodes, group.links
     uv = nodes.new("GeometryNodeInputNamedAttribute")
@@ -33,7 +33,8 @@ def original_boundary_field(group, original):
     nearest.domain = "POINT"
     links.new(original_uv.outputs["Geometry"], nearest.inputs["Geometry"])
     links.new(uv.outputs["Attribute"], nearest.inputs["Sample Position"])
-    rim = evaluate_field(group, edge_boundary_field(nodes, links), "FLOAT", "POINT")
+    if rim is None:
+        rim = evaluate_field(group, edge_boundary_field(nodes, links), "FLOAT", "POINT")
     return sample_field(group, original, rim, "FLOAT", index=nearest.outputs["Index"])