bump cadgenbench -> 68e9337 (clamp edit-diff zoom to full view)

Dockerfile

@@ -41,7 +41,7 @@ RUN pip install --no-cache-dir -r /tmp/requirements.txt \
 # image rebuild picks up the latest code (pre-v1: always-updated). Lock
 # to a specific commit SHA at the v1 release so published scores are
 # reproducible (see space-setup/post-gt-swap.md Stage F).
-ARG CADGENBENCH_SHA=2b1c939
+ARG CADGENBENCH_SHA=68e9337
 # Cache-bust the install below whenever the tracked ref moves: the
 # GitHub commits endpoint's response changes with each new commit on
 # `main`, so BuildKit re-fetches and invalidates the cached pip layer.