Account deletion now removes your uploaded images too

A follow-up to this morning's account-deletion improvement, and an honest note about it: that change covered your activity records, but images you had uploaded were still left behind in our image hosting. Those were your avatar, and images attached to your critique submissions.

Fixed. Deleting your account now removes those images as part of the same strict, all-or-nothing cleanup: if any of it can't be removed, the deletion doesn't proceed and you're asked to try again.