feat: Add BEN2 background removal functionality and integrate into SnapForm

- Introduced BEN2 model for background removal in the panel and properties.
- Updated runtime to handle background removal commands and model downloads.
- Implemented background removal logic in worker, including image processing and saving results.
- Enhanced tests to cover new background removal features and ensure proper integration.
- Updated version to 0.9.28 to reflect new features and improvements.

src/snapform/panel.py

@@ -1,6 +1,6 @@
 import bpy
 
-from .models import MODELS
+from .models import BEN2_MODEL, MODELS
 from .operators import active_job
 from .runtime import model_ready, runtime_ready
 
@@ -29,6 +29,7 @@ class RuntimeModelsPanel(bpy.types.Panel):
 
         for model in MODELS.values():
             self._draw_model(layout, model, running)
+        self._draw_model(layout, BEN2_MODEL, running)
 
     def _draw_model(self, layout, model, running):
         row = layout.row(align=True)
@@ -106,3 +107,15 @@ class DebugPanel(bpy.types.Panel):
             icon="EXPORT",
         )
         operator.job_type = "RECONSTRUCT"
+
+        background_box = layout.box()
+        background_box.label(text="BEN2 Background Removal")
+        background_box.prop(settings, "background_input_path")
+        background_row = background_box.row()
+        background_row.enabled = active_job() is None
+        operator = background_row.operator(
+            "snapform.run_job",
+            text="Remove Background",
+            icon="IMAGE_ALPHA",
+        )
+        operator.job_type = "REMOVE_BACKGROUND"