Record the digests of the images that went out

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

CHANGELOG.md

@@ -10,9 +10,10 @@ not from the output of `docker push`.
 
 ## 2026-08-17 — Three things that only showed on screen
 
-**Images** — web `sha256:PENDING`, server `sha256:PENDING`
+**Images** — web `sha256:c5e460cf…`, server `sha256:ac3b0527…`
 
-No backend source changed this round.
+No backend source changed this round; the server digest moved only because
+`build.sh` builds both and a rebuild is not bit-identical.
 
 **Fixed**
 - **Grey letters ran down the bar while dragging a column edge.** The editor