Chenghui-Liang/dsh-web-pick

Adds an element and region picker to the DSH Desktop built-in browser: hovering labels the element under the pointer, a click records that element, a drag records a rectangle, and each pick opens a small note box beside the pick. A batch is then inserted into the composer draft, never sent automatically, as one text block plus one attached crop per pick, so the user reviews and sends it themselves. Desktop only: the Web profile browser is an iframe, so the picker does not appear there.