docs: show new ui as screenshots in the readme

CLAUDE.md

@@ -72,6 +72,12 @@ when you press Enter." The list of commits follows on its own.
 - To change an old release: edit its entry, commit, then
   `gh release edit <tag> --title <tag> --notes "$(.github/release-notes.sh <tag>)"`.
 
+## README
+
+- New UI (a window, a screen, a menu, a setting, a notification) gets a screenshot in the README,
+  next to the text about it. Like for releases: a real screenshot of it running, in English.
+- When a screen changes, take its screenshot again. The README never shows an old one.
+
 ## Testing
 
 Never test against the real setup: `enable` and `apply` rewrite the user's file associations.