The circular dependency error '_pypi/psutil → _pypi/psutil' occurred because
dependencies with extras like 'psutil[test]' weren't being recognized as
self-dependencies. The comparison 'psutil[test] != psutil' failed.
- Add _normalize_pypi_package_name() helper that strips extras brackets
and normalizes separators per PEP 503
- Update _detect_package_cycle to use normalized names for cycle detection
- Update check_circular_dependencies to use normalized initial path
- Simplify self-dependency check in resolve_dependencies to use helper
281474d72f