QTZPOC-20: Enhance system robustness and test coverage across bundle processing, activity error handling, and worker operations.
* Strengthen bundle reader validation with new tests for archive integrity, security vulnerabilities (e.g., path traversal, duplicate entries, special file types), and I/O error resilience.
* Improve error handling and status propagation in PI Web API, MLflow, and OPC activities, including partial write scenarios and OPC session management.
* Add comprehensive tests for worker startup, configuration, graceful shutdown, and Prometheus metrics server initialization.
* Introduce a new utility for intelligent DataFrame debugging, summarizing large dataframes for concise logging, and refine exception chain summarization.
* Update code coverage configuration to exclude @overload decorator lines.
