feat: implement complete CMT backend with API endpoints and test suite

- Add 7 core API endpoints: users, transactions, partners, products, inventory, payments, credit
- Implement role-based authentication (admin/write/read-only access)
- Add comprehensive database models with proper relationships
- Include full test coverage for all endpoints and business logic
- Set up Alembic migrations and Docker configuration
- Configure FastAPI app with CORS and database integration

backend/pyproject.toml

@@ -0,0 +1,7 @@
+[tool.pytest.ini_options]
+minversion = "6.0"
+addopts = "-ra -q --strict-markers"
+testpaths = ["tests"]
+python_files = ["test_*.py"]
+python_classes = ["Test*"]
+python_functions = ["test_*"]