Allow assigning the same image to multiple options

• Default: Disabled
• When this setting is active, you can assign a single image to more than one variant option (e.g., both “Black” and “White”).
• This is especially useful for shared assets such as packaging, model shots, or universal brand visuals.

✅ Best for stores that sell products with visual similarities across options.

If disabled, Rubik will prevent images from being assigned to multiple options, enforcing stricter image-variant relationships.