Refactor image mesh processing and background removal functionality

- Updated NODE_GROUP_NAME from "O Refine DA3 Surface" to "O DA3 Surface".
- Introduced `remove_surface_background` function to filter out background faces and compact geometry.
- Enhanced `build_image_mesh` to conditionally remove background faces based on a new property.
- Added `snapform_remove_background` and `snapform_keep_original` properties to operators for better control over background handling.
- Updated UI to reflect new properties and improved resolution scaling logic.
- Refactored tests to cover new background removal functionality and ensure proper geometry handling.
- Adjusted geometry nodes and validation scripts to remove references to background handling.

src/snapform/operators.py

@@ -328,8 +328,6 @@ class RunJob(bpy.types.Operator):
         remove_background = bool(
             getattr(self, "snapform_remove_background", False)
         )
-        if self.job_type == IMAGE_MESH_JOB:
-            remove_background = True
         if self.job_type == "INSTALL_RUNTIME":
             self._require_online_access()
             return runtime.install_runtime_command(paths["status"]), paths
@@ -723,6 +721,7 @@ class RunJob(bpy.types.Operator):
             snapform_delete_source=job.delete_source,
             snapform_create_camera=job.mesh_create_camera,
             snapform_unshaded=job.unshaded,
+            snapform_remove_background=job.remove_background,
         )
         if "FINISHED" not in result:
             raise RuntimeError("Unable to build the perspective surface")