feat: Implement depth cutout symmetry and associated functionalities

- Introduced a new proposal for depth cutout symmetry, allowing for the reuse of depth replacement and geometry operations.
- Added requirements for maintaining default thickness values for cutout nodes and ensuring proper initialization during object creation.
- Enhanced symmetry node to handle existing geometry, including alignment, mirroring, and boundary filling.
- Implemented fill smoothing to control the geometry of generated walls while preserving original surfaces.
- Created tests to validate the functionality of the new symmetry features against baseline geometry.
- Updated existing assets and node groups to support the new symmetry capabilities without introducing additional dependencies.

tests/support/nodes.py

@@ -1,11 +1,11 @@
 """Shared assertions and asset selection for node tests."""
 from tools.nodes.groups.image_cutout import build_image_cutout_group
 from tools.nodes.groups.image_depth_cutout import build_image_depth_cutout_group
-from tools.nodes.groups.image_depth_symmetry import build_image_depth_symmetry_group
+from tools.nodes.groups.image_cutout_symmetry import build_image_cutout_symmetry_group
 
 CUTOUT_BUILDERS = {
     "FLAT": build_image_cutout_group,
     "SOLID": build_image_cutout_group,
     "DEPTH_SOLID": build_image_depth_cutout_group,
-    "DEPTH_SYMMETRY": build_image_depth_symmetry_group,
+    "DEPTH_SYMMETRY": build_image_cutout_symmetry_group,
 }