Moved convertToImage, createMaskFromImageSrc, and canvasToMaskImage from MaskProcessingUtils and mask_utils to ImageUtils for better modularity and reuse. Updated imports in dependent modules to use the new locations. Removed duplicate implementations from mask_utils and MaskProcessingUtils.
Introduces the ability to open the current canvas in a mask editor, upload and retrieve mask edits, and apply them to the mask layer. Adds utility functions for mask editor state detection and control, a new 'Edit Mask' button in the UI, and methods for handling mask updates and preview refresh. Also adds a setMask method to MaskTool for precise mask placement.
