Catch box missing credentials

If you don't have a box.env you get a pydantic crash. it would be better if it catches it and gives a useful error.

Start by running the pEyeON file manifest tool without a box.env file and trace the configuration path where the Pydantic crash occurs. Identify the existing error-handling entry point, then verify that the missing credentials produce a useful error instead of an unhandled crash.

Written by the indexing model from the issue text.