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_plane_objects.py

@@ -143,7 +143,6 @@ def test_converted_planes_center_the_origin_without_moving_world_corners():
         _depth_metadata(
             ((0.5, 0.0, 0.5), (0.0, 0.5, 0.5), (0.0, 0.0, 1.0)),
             (2, 2),
-            1.0,
         ),
         "DEPTH",
     )
@@ -192,7 +191,6 @@ def test_relief_plane_builds_a_fixed_base_terrain_block():
         _depth_metadata(
             ((1.5, 0.0, 1.5), (0.0, 1.5, 1.5), (0.0, 0.0, 1.0)),
             (4, 4),
-            1.0,
         ),
         "RELIEF",
     )
@@ -208,7 +206,7 @@ def test_relief_plane_builds_a_fixed_base_terrain_block():
     ] == 0.5
     assert modifier[
         object_data.modifier_input_identifier(group, "Depth Offset")
-    ] == 1.0
+    ] == 0.0
 
     def set_input(name, value):
         object_data.set_modifier_input(
@@ -299,7 +297,6 @@ def test_relief_plane_initializes_a_fitted_depth_direction():
     metadata = _depth_metadata(
         ((2.0, 0.0, 2.0), (0.0, 2.0, 1.0), (0.0, 0.0, 1.0)),
         (5, 3),
-        2.0,
     )
     result = plane_object.create_depth_plane_object(
         bpy.context,