Improve robustness of graph cycle detection code

You have written code to detect cycles in a directed dependency graph of services, where nodes represent services and edges represent dependencies between services. In a real-world production environment, this code will be part of a larger system that validates service configurations before deployment. **Question:** How would you improve this cycle detection component so that it works better in a real-world setting? Discuss considerations and potential improvements in areas such as: - Code readability and maintainability - Handling large-scale graphs (performance, memory) - Error handling and edge cases (e.g., invalid or missing data) - Logging, monitoring, and observability - Testing strategy (unit tests, integration tests, property-based tests) - API design (inputs/outputs, how results are surfaced to other services or to users) - Extensibility for future requirements (e.g., reporting all cycles, not just existence) Provide concrete examples and rationale for the improvements you propose.