Enhance image editing tests and functionality

- Added parameterized tests for image edit replacement to ensure alpha mode preservation.
- Refactored existing tests to utilize new image editing methods and improve clarity.
- Introduced new tests for image target functionality, ensuring proper handling of shared textures and context.
- Updated various tests to validate alpha mode handling across different scenarios.
- Improved undo/redo functionality in image operators to maintain state consistency.
- Added support for texture node actions, enhancing integration with Blender's node system.
- Ensured that image properties are preserved during operations and that invalid contexts are handled gracefully.

tests/anyimage/operators/test_frame_antialiasing.py

@@ -126,7 +126,7 @@ def test_packed_frame_mask_add_keeps_boundary_color(background):
         ).reshape(1, 1, 4)
         np.testing.assert_allclose(restored[0, 0, :3], expected, atol=1 / 255)
         assert restored[0, 0, 3] == 1
-        assert result.alpha_mode == "PREMUL"
+        assert result.alpha_mode == "STRAIGHT"
     finally:
         bpy.data.images.remove(original)
         bpy.data.images.remove(result)