Record the digests of the images that went out

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

CHANGELOG.md

@@ -10,7 +10,11 @@ not from the output of `docker push`.
 
 ## 2026-08-12 — A chapter you can see, in the colour you chose
 
-**Images** — web `sha256:…`, server unchanged at `sha256:ed0b9970…`
+**Images** — web `sha256:65799ecb…`, server `sha256:a51b96ad…`
+
+No backend source changed this round. The server digest moved anyway because
+`build.sh` builds both images and a rebuild is not bit-identical — the image is
+the same code as `sha256:ed0b9970…`.
 
 **Fixed**
 - **A chapter did not show until the notebook had a note in it.** "Nothing here"