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.

tools/nodes/groups/image_depth_plane.py

@@ -45,8 +45,6 @@ def build_image_depth_plane_group(image_plane_group):
     valid_only.description = "Remove mesh areas marked invalid by the depth mask."
     valid_only.default_value = True
     options = group.interface.new_panel(name="Options", default_closed=True)
-    float_input(group, "Smooth Weight", 1.0, maximum=1, subtype="FACTOR", parent=options).description = "Control the strength of boundary smoothing. Higher values move boundary vertices more."
-    float_input(group, "Reference Depth", 1.0, subtype="DISTANCE", parent=options)
     boundary_smooth = _interface_socket(group, "Boundary Smooth", "INPUT", "NodeSocketInt", parent=options)
     boundary_smooth.default_value, boundary_smooth.min_value, boundary_smooth.max_value = 4, 0, 16
     boundary_smooth.description = "Smooth depth and geometry near cut edges while preserving the original image border. Zero disables boundary smoothing."
@@ -55,6 +53,7 @@ def build_image_depth_plane_group(image_plane_group):
     validity_threshold.default_value = 0.9
     validity_threshold.min_value, validity_threshold.max_value = 0.0, 1.0
     validity_threshold.subtype = "FACTOR"
+    float_input(group, "Reference Depth", 1.0, subtype="DISTANCE", parent=options)
     data = group.interface.new_panel(name="Data", default_closed=True)
     uniform_scale = _interface_socket(
         group,