Implement PostgreSQL Business Data Layer

Set up the PostgreSQL Business Data Layer that will be used for both dataset storage and output data. This replaces the current Twin Data Layer for dataset storage and provides the foundation for the new architecture.

**Estimate**: 1-2 weeks
**Due Date**: August 1, 2025
**Task Number**: #14

This task was automatically generated from meeting notes dated June 12, 2025 and June 16, 2025.