chore: media compression feature groundwork

docs/design/screens/media.md

@@ -36,6 +36,10 @@ Detail panel copy:
 | Used | "Used in 2 articles", then one row per article: title (underlined link to the editor), badge "Online" (`globe`, inverted) or "Draft" (`pencil-line`, outline), `arrow-up-right`. Footnote: "Counted from the text of your articles each time you open this page." |
 | Not used | "Not used in any article" / "This image is safe to delete. No article shows it." |
 
+## Image variants
+
+The Library gains a "N variants" badge, an All / With variants / Without filter, the sort option "Largest total size (original + variants)", a delete dialog that names the generated variants it removes, and a Variants tab in the detail panel. Those states are in [image-variants](image-variants.md), sections 3 and 4.
+
 ## Dialogs
 
 All dialogs use the existing ConfirmDialog look (`UModal`, `sm:max-w-md`, bottom sheet on mobile, cancel first). While a request runs the confirm button shows a `loader-circle`, both buttons are disabled and the dialog cannot be dismissed. A failure shows an error alert at the top of the dialog body and the dialog stays open.