Refactor image processing and cutout functionalities

- Updated the naming convention for upscaled images to include underscores and file extensions.
- Renamed properties related to cutout pixel size to point spacing for clarity.
- Adjusted alpha region calculations to use a half-alpha threshold for better accuracy.
- Enhanced the handling of foreground mesh masks to consider half-alpha values.
- Introduced new functions for unbounded selections and cutout images, ensuring proper handling of source and selection images.
- Improved test coverage for cutout functionalities, including bounds mapping and alpha preservation.
- Updated tests to reflect changes in naming conventions and functionality adjustments.

src/anyimage/properties.py

@@ -332,11 +332,11 @@ def cutout_normal_analysis_property():
         default=False,
     )
 
-def cutout_pixel_size_property():
+def cutout_point_spacing_property():
     return bpy.props.IntProperty(
-        name="Pixel Size",
+        name="Point Spacing",
         description=(
-            "Approximate source image pixels per mesh step; smaller values "
+            "Source image pixels between neighboring mesh points; smaller values "
             "create denser geometry"
         ),
         default=32,
@@ -372,7 +372,7 @@ def balloon_radial_zoom_property(scale):
 
 
 class AnyImageSettings(bpy.types.PropertyGroup):
-    cutout_pixel_size: cutout_pixel_size_property()
+    cutout_point_spacing: cutout_point_spacing_property()
     cutout_normal_analysis: cutout_normal_analysis_property()
     image_edit_refine_selection: image_edit_refine_selection_property()
     balloon_mode: balloon_mode_property()