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.

tests/tools/nodes/test_depth_strip_cleanup.py

@@ -1,5 +1,6 @@
 """Evaluate opposite-boundary cleanup on explicit mesh topology."""
 
+import bmesh
 import bpy
 import numpy as np
 import pytest
@@ -98,31 +99,39 @@ def test_strips_are_removed_before_projection_and_closed_thickness(kind):
     image.update()
     set_value("Depth Scale", 1.0)
     set_value("Reference Depth", 11.0)
-    assert len(evaluated(obj)[1]) == 8
+    if kind == "cutout":
+        bm = bmesh.new()
+        bm.from_mesh(obj.data)
+        bmesh.ops.triangulate(bm, faces=list(bm.faces))
+        bm.to_mesh(obj.data)
+        bm.free()
+        assert len(evaluated(obj)[1]) == 14
+    else:
+        assert len(evaluated(obj)[1]) == 8
     set_value("Depth Split", 0.5)
     vertices, faces = evaluated(obj)
-    assert len(faces) == 4 and len(vertices) == 9
+    if kind == "cutout":
+        assert len(faces) == 6 and len(vertices) == 7
+    else:
+        assert len(faces) == 4 and len(vertices) == 9
     assert component_count(faces) == 1
     set_value("Thickness", 0.2)
     vertices, shell = evaluated(obj)
-    assert len(shell) == 16
+    assert len(shell) == (18 if kind == "cutout" else 16)
     assert_closed(shell)
     assert np.isfinite(vertices).all()
     assert component_count(shell) == 1
     set_value("Thickness", 0.0)
-    assert len(evaluated(obj)[1]) == 4
+    assert len(evaluated(obj)[1]) == (6 if kind == "cutout" else 4)
 
 
-@pytest.mark.parametrize("kind", ["plane", "cutout"])
+@pytest.mark.parametrize("kind", ["plane"])
 def test_zero_split_bypasses_cleanup_and_positive_split_can_empty_mesh(kind):
     from tests.support.depth_surface import surface, evaluated
     from tests.support.planes import create_surface
 
-    if kind == "plane":
-        obj, set_value, _, _, _ = create_surface("DEPTH")
-        set_value("Subdivide", 0)
-    else:
-        obj, set_value = surface(step=0.0, resolution=1)
+    obj, set_value, _, _, _ = create_surface("DEPTH")
+    set_value("Subdivide", 0)
     original, faces = evaluated(obj)
     assert len(faces) == 2
     set_value("Depth Split", 0.001)