Record the digests of the images that went out

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

CHANGELOG.md

@@ -10,7 +10,10 @@ not from the output of `docker push`.
 
 ## 2026-08-12 — A notebook opens in its own order
 
-**Images** — web `sha256:…`, server unchanged in substance
+**Images** — web `sha256:c077f0e0…`, server `sha256:c13af5d5…`
+
+No backend source changed this round; the server digest moved only because
+`build.sh` builds both and a rebuild is not bit-identical.
 
 **Fixed**
 - **Removing a chapter left you stuck in the confirmation.** Every destructive