- Introduced `pyproject.toml` to centralize backend tool configurations (e.g., Ruff, mypy, coverage, pytest).
- Replaced Black, isort, and Flake8 with Ruff for linting, formatting, and import sorting.
- Updated `requirements.txt` to include Ruff and remove replaced tools.
- Added `Makefile` to streamline development workflows with commands for linting, formatting, type-checking, testing, and cleanup.
- Introduced comprehensive tests for session CRUD error cases, covering exception handling, rollback mechanics, and database failure propagation.
- Added robust API error handling tests for admin routes, including user and organization management.
- Enhanced test coverage for unexpected errors, edge cases, and validation flows in session and admin operations.
