Add a textual setting, which is used as the watermark text
Stretch goals
Add a custom display for CardItems that show 2 cards, one regular, and one Saga layout.
Make the watermark movable via drag&drop during configuration. Sync movement between the two previews.
Add an angle setting to rotate the watermark
Add a color selector to set the watermark color and opacity. Maybe use a slider for the opacity, since the transparency option in the Qt color selector isn't great