Dependency Groups (PEP 735 Implementation)

The `dependency-groups` library is an active implementation of PEP 735, a standard defining a mechanism for storing package requirements in `pyproject.toml` files that are not included in built project metadata. This library, currently at version 1.3.1 and maintained by the Python Packaging Authority, enables parsing and resolving these dependency groups, including handling nested group inclusions. It's primarily used for development-time dependencies like testing, linting, or documentation, distinguishing them from runtime or optional user-facing dependencies.