Signed 0.1.0

First release of Signed: sign PDFs and fill them in with text and dates.

• Place saved signatures, text, and today's date anywhere on a page, at the mouse pointer.
• Drag to move, drag the corner to scale, double-click text to edit. Undo and redo.
• Add signatures from a scan or photo; the paper is removed and the ink kept.
• Save a signed copy beside the original. The original pages stay as they are: text stays selectable and nothing is re-rendered.
• Keyboard first: press ? for every hotkey.

Requires poppler-qt6, qpdf, noto-fonts, and xdg-desktop-portal.