Saving works after replacing an image on a duplicated slide
Fixed "Save failed" after duplicating a slide and replacing or clearing an image on one copy, and fixed buttons breaking when the side panel is narrow.
After duplicating a slide, replacing or clearing an image on one of the two copies caused saving to fail with Save failed. This affected screenshots, zoom callout images and custom background images. Each copy now keeps its own image, and saving works.
When the side panel was narrow, the theme button grew taller and the Export PNG label overflowed its button. Long labels are now shortened, and the full text appears when you hover.