Refactor depth reference handling and cleanup

- Unified reference depth calculation to use a single implementation in common/depth.py.
- Removed server-side reference depth computation and adjusted depth.json to only include image_size and intrinsics.
- Updated depth texture handling to ignore transparent, invalid, and non-positive pixels when calculating reference depth.
- Changed reference depth calculation to use the 95th percentile of valid depth values.
- Adjusted depth direction fitting to return a flat direction when no samples are available.
- Removed cleanup threshold parameters from Cutout and related nodes, simplifying the interface.
- Updated tests to verify new reference depth logic and ensure compatibility with existing functionality.

tests/anyimage/operators/test_cutout_edge_length.py

@@ -118,25 +118,30 @@ def test_operator_length_property_accepts_world_units():
         bpy.utils.unregister_class(CutoutLengthTestOperator)
 
 
-def test_effective_length_report_and_geometry_share_value():
+def test_effective_length_report_and_geometry_build_share_value():
     report = Mock()
     context = SimpleNamespace(scene=SimpleNamespace(unit_settings=SimpleNamespace(system="METRIC", scale_length=0.01)))
+    source = object()
+    content = np.ones((10, 10))
     with patch.object(operators, "effective_cutout_edge_length", return_value=20), \
          patch.object(operators, "build_base_shape") as build, \
          patch.object(operators, "create_shape_object") as create, \
          patch.object(operators.bpy.ops.ed, "undo_push", return_value={"FINISHED"}):
         operators.create_cutout_shape(
             context,
-            object(),
+            source,
             "FLAT",
             10,
-            np.ones((10, 10)),
+            content,
             (0, 0, 10, 10),
             boundary_padding=0.0,
             color_image=object(),
             report=report,
         )
     assert build.call_args.args[2] == 20
-    assert create.call_args.args[3] == 20
+    assert create.call_args.args[0] is context
+    assert create.call_args.args[1] is source
+    assert create.call_args.args[2] == "FLAT"
+    assert create.call_args.args[3] is content
     assert report.call_args.args[0] == {"INFO"}
     assert "20 cm" in report.call_args.args[1]