Add comprehensive tests for edge depth extension, empty image edits, and material view adaptation

- Introduced `test_edge_depth.py` to validate the functionality of edge depth extension, ensuring core alpha preservation, proper depth handling, and edge padding behavior.
- Created `test_empty_image_edits.py` to verify the behavior of image edits in Blender, focusing on shared edits, preservation of image properties, and handling of failed operations.
- Developed `test_material_view_adaptation.py` to test material adaptation preferences, ensuring color space and alpha settings are correctly applied and preserved across various scenarios.

src/anyimage/operators/cutout_tool/object.py

@@ -17,6 +17,7 @@ from ...common.object import (
 )
 from ...common.node import load_node_group
 from .geometry import (
+    CUTOUT_ALPHA_THRESHOLD,
     DEFAULT_DEPTH_BASELINE,
     DEFAULT_DEPTH_DIRECTION,
     crop_plane_bounds,
@@ -161,6 +162,7 @@ def create_shape_object(
     content_bounds,
     base_shape,
     *,
+    alpha_threshold=CUTOUT_ALPHA_THRESHOLD,
     depth_image=None,
     depth_metadata=None,
     normal_image=None,
@@ -213,7 +215,7 @@ def create_shape_object(
                 raise ValueError("Depth Shape requires a Depth texture and metadata")
             camera_depth, valid = camera_depth_values(depth_image)
             calibration_valid, transparent_fraction = selection_calibration(
-                content_values, valid.shape
+                content_values, valid.shape, threshold=alpha_threshold
             )
             calibration_valid &= valid
             uniform_scale = depth_uniform_scale(