Add multi-database support allowing selection between SQL Server and
PostgreSQL via database.active config. Changes include dialect-aware
SQL generation, cross-database timestamp functions, PostgreSQL connection
URL builder, and psycopg dependency.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
- Add test_config.py with tests for load_settings function
- Add test_config.yaml fixture with test database configuration
- Tests cover: successful loading, file not found error, database URL generation
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
