Backend Structure and Initial Implementation

[sincover]

Description

This PR adds the backend structure and initial implementation for the Executive Orders Archive project:

Key Components

• Flask application setup with proper configuration
• Database models for executive orders with SQLAlchemy
• API routes for retrieving executive orders
• Utility functions for HTTP responses, database operations, and data transformation
• GitHub Actions workflow for automated testing

Next Steps

• Complete data fetching services from Federal Register API
• Implement full-text search capabilities
• Add more comprehensive tests

Testing

Basic unit and integration tests have been added. The CI workflow will run these tests automatically.

Dependencies

• Flask
• SQLAlchemy
• PostgreSQL (for production) / SQLite (for testing)