Add kardex CLI scaffolding and clarify environment errors

[phenobarbital]

Summary

• add a kardex console entry point that scaffolds the expected env and etc directories
• clarify the loader and initialization errors with guidance to run the new CLI when the env folder is missing
• cover the CLI scaffolding path with a unit test

Testing

• pytest (fails: missing optional test dependencies such as pytest_asyncio and navconfig importable package during example collection)

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https://chatgpt.com/codex/tasks/task_e_68ec71d984e08330a83d4088bb7de90d