Decouple CLI commands from internal helper logic and consolidate the
core file transfer operations in the service layer to improve library
portability.
- Make MdrsClient subclass MdrsService to inherit resource resolution.
- Remove all deprecated helper methods from BaseCommand.
- Move core upload and download logic to a new transfer module.
- Refactor all CLI commands to route actions through MdrsClient.
- Eliminate circular imports between client and CLI command modules.
