Add image selection refinement functionality with BEN2 integration

- Implemented viewport.py for handling 3D view projections, gestures, and overlay drawing.
- Created refine_image_selection.py to manage the refinement of gesture masks and output image bounds.
- Added selection module with refine_selection.py to process and crop images based on alpha channel visibility.
- Introduced __init__.py for selection module to expose refine_selection function.

src/anyimage/operators/__init__.py

@@ -1,7 +1,7 @@
 from .remove_background import RemoveImageBackground, RunBackgroundRemoval
 from .cutout_tool import (
-    CutoutRegionToShape,
-    SelectCutoutRegion,
+    CutoutSelectionToShape,
+    SelectCutoutSelection,
 )
 from .debug import DebugBen2, DebugDa3, DebugMoge2, DebugUpscale
 from .image_tool import CLASSES as IMAGE_TOOL_CLASSES
@@ -31,8 +31,8 @@ CLASSES = (
     DebugBen2,
     DebugUpscale,
     GenerateDepthPlane,
-    CutoutRegionToShape,
-    SelectCutoutRegion,
+    CutoutSelectionToShape,
+    SelectCutoutSelection,
     RunBackgroundRemoval,
     ClearModels,
     *IMAGE_TOOL_CLASSES,