feat: Implement weight cutout boundary smoothing for image depth cutout

- Added a new proposal for boundary smoothing in the weight cutout process, differentiating between Split edges and Outline smoothing requirements.
- Introduced a new capability `cutout-boundary-smoothing` to control smoothing strength and default values.
- Updated specifications to define the behavior of boundary-specific smoothing strength and default settings.
- Created tasks to verify the implementation of boundary behavior and asset updates.
- Developed comprehensive tests for depth symmetry and normal scaling to ensure expected behavior and performance.
- Introduced new attributes for normal mapping to facilitate persistent face attributes sharing between depth symmetry and image materials.
- Built a new node group for O Image Depth Symmetry, integrating the new smoothing capabilities and ensuring compatibility with existing workflows.

tests/anyimage/operators/test_cutout_depth.py

@@ -10,7 +10,7 @@ from anyimage.operators.cutout_tool.balloon import poisson_balloon_profile
 @pytest.mark.parametrize("enabled", [False, True])
 def test_depth_presets_always_generate_the_correct_normal_space(enabled):
     assert normal_mode_for_shape("DEPTH_SOLID", enabled) == "OBJECT"
-    assert normal_mode_for_shape("DEPTH_BALLOON", enabled) == "TANGENT"
+    assert normal_mode_for_shape("DEPTH_SYMMETRY", enabled) == "TANGENT"
     for shape in ("FLAT", "SOLID"):
         assert normal_mode_for_shape(shape, enabled) == ("TANGENT" if enabled else "NONE")