Implement CSV/JSON converter and fix single object validation check

[8Ashwinee]

Closes #10

• Implemented a robust csv_json_converter.py utility under the scripts/ directory using standard library modules (csv, json, sys).
• Supports bi-directional conversion handled dynamically via file extensions (.csv <-> .json).
• Configured robust edge-case validation to gracefully catch structural JSON errors and handle single flat objects.
• Tested local round-trips against data/demo.json seamlessly.