- Add hasattr(sd, 'expression') guard in engine fixtures to prevent
AttributeError when iterating over server_default columns that use
DefaultClause (which lacks .expression)
- Add _build_engine_kwargs() in database.py to conditionally apply
pool_size/max_overflow only for non-SQLite database URLs
- Fixes test failures in conftest.py, test_encrypted_json.py
Co-Authored-By: Paperclip <noreply@paperclip.ing>