fix: emit full commit sha as ref — git fetch rejects abbreviated ids

The tagless fallback truncated the sha to 12 chars for the version string
and reused that as ref, so the upstream fetch failed with
'couldn't find remote ref'. Keep the full sha for ref, shorten only the
version suffix.

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

scripts/get-latest-version.sh

@@ -24,8 +24,9 @@ if [ -n "$tag" ]; then
   echo "version=${tag#v}"
   echo "ref=$tag"
 else
-  sha=$(git ls-remote "$UPSTREAM_URL" refs/heads/main | cut -c1-12)
+  # ref must stay the full sha: `git fetch <sha>` rejects abbreviated ids.
+  sha=$(git ls-remote "$UPSTREAM_URL" refs/heads/main | awk '{print $1}')
   [ -n "$sha" ] || { echo "ERROR: cannot resolve upstream main" >&2; exit 1; }
-  echo "version=0.0.0-git.$sha"
+  echo "version=0.0.0-git.${sha:0:12}"
   echo "ref=$sha"
 fi