Misusage of `litebox_packager` in a non-dev environment

Using `litebox_packager` in a non-development environment potentially results in unexpected errors. We might want to harden it to prevent users from misusing it.

The issue identifies litebox_packager as the affected entry point but names no file, test, or concrete failure. Start by locating its implementation and reproducing its behavior in a non-development environment; completion should define and verify safe behavior for that use case.

Written by the indexing model from the issue text.