Support Windows ICO in image edit and background remove.

Decode the largest BMP or PNG frame for editing, export PNG-in-ICO, and open .ico from the home drop zone.

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/frontend/src/config/favicons.ts

@@ -159,6 +159,7 @@ const EXT_KIND: Record<string, FaviconKind> = {
   bmp: 'scanner',
   bgremove: 'bgremove',
   imgedit: 'imgedit',
+  ico: 'imgedit',
   txt: 'text',
 };