Refactor depth node groups and simplify options

- Removed `Smooth Weight` input from `O Image Depth Plane`, `O Image Depth Cutout`, and `O Image Depth Panorama` to streamline the interface and maintain consistent boundary smoothing behavior.
- Adjusted the `Reference Depth` input to appear last in the options panel for better organization, reflecting its role as a calibration value.
- Consolidated the `expand_smooth()` function to only accept necessary parameters, eliminating unused branches related to `Smooth Weight` and `pin_sharp`.
- Updated related tests and node assets to ensure functionality remains intact and consistent with the new structure.
- Introduced new specifications to document the changes and ensure compliance with the updated requirements.

tests/tools/nodes/test_image_depth_panorama.py

@@ -132,7 +132,8 @@ def test_controls_and_material_slot_inheritance():
     assert inputs["Invalid Distance"].parent.name == "Options"
     assert inputs["Invalid Distance"].default_value == 100
     assert inputs["Invalid Distance"].subtype == "DISTANCE"
-    assert inputs["Smooth Weight"].parent.name == "Options"
+    assert inputs["Boundary Smooth"].parent.name == "Options"
+    assert "Smooth Weight" not in inputs
     assert inputs["Depth Mask"].parent == inputs["Subdivide"].parent
     assert inputs["Depth Mask"].default_value
     obj.data.from_pydata([(0, 0, 0)], [], [])