* One pool for all the images. Every picture carries two ticks — background or
  text, never both — with a select-all per column; neither ticked keeps it on
  hand, unused. The text can now cycle several images, on the slideshow's rules.
* The settings screen got a redesign: rounded cards on black, one accent colour,
  compact controls that fit a narrow screen. Tap an image's name to rename it.
