Apple has unveiled the iPhone Duo, its first foldable phone. When closed, it measures 84.1 x 117.8 x 11.3 mm, and when opened it offers a tablet-style display of 164.6 x 117.8 mm with a thickness of only 5.2 mm, thinner than the iPhone Air. It weighs 254 grams and starts at 54,990 Czech korunas,…