The todo-backend Dockerfile (and potentially other backends) expect this script
to exist in docker/shared/. This script builds shared packages in dependency
order during Docker image builds.
Fixes CI failure: "ERROR: failed to build: /docker/shared/build-shared-packages.sh: not found"
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude <noreply@anthropic.com>
