c60a1006e5
As part of the brush assets project, the image editor needs an asset shelf to display brush assets for texture paint mode. This commit adds the unused asset shelf region, similar to the 3D viewport's region that is currently just used for the pose library. For now, users will just see an "Asset Shelf" toggle in the view menu. Pull Request: https://projects.blender.org/blender/blender/pulls/121034