A watermark (text, horizontal or vertical, or a graphic) can be turned 0,
90, 180 or 270 degrees clockwise, like Lightroom Classic's rotate buttons.
It is sized before it is turned and placed and inset by the turned box; the
shadow still falls down and to the right. New watermark key `rotation`
(other values are errors); settings without it draw unturned. The Export
dialog gets a Rotate row.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>