open https://gitlab.synchro.net/main/sbbs/-/issues/485

Normally, MIME-attachments are decoded and available for downloaded when reading an email. This isn't working with the latest iOS/iPhones (single photo attachment).Example problematic message body:```--Apple-Mail-C3E7F37A-1CD1-4CB5-A10C-F13DD02CA284Content-Type: text/plain; charset=us-asciiContent-Transfer-Encoding: 7bit--Apple-Mail-C3E7F37A-1CD1-4CB5-A10C-F13DD02CA284Content-Type: image/jpeg; name=IMG_6632.JPEG; x-apple-part-url=FC4DCFCB-47EE-4BFB-973D-926D64305DA0Content-Disposition: inline; filename=IMG_6632.JPEGContent-Transfer-Encoding: base64/9j/4AAUSkZJRgABAQEBLAEsAABBTVBG/+EKhEV4aWYAAE1NACoAAAAIAA4BDwACAAAABgAAALYB ...```
--- SBBSecho 3.20-Linux
* Origin: Vertrauen - [vert/cvs/bbs].synchro.net (1:103/705)