fix: pull --rebase before push in commit step to avoid race condition

If the remote advances between the workflow's checkout and its commit
step (e.g., another push lands in between), the push was rejected.
Now we rebase onto the latest remote HEAD before pushing.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: TheSmallPixel

action.yml

@@ -75,6 +75,7 @@ runs:
           echo "No changes to commit."
         else
           git commit -m "Update code graph JSON & index [skip ci]"
+          git pull --rebase origin "${GITHUB_REF#refs/heads/}"
           git push
         fi
       shell: bash