fix: collect and manage generated files from job executions (#50)

* feat(execution): collect and manage generated files from jobs

* Add functionality to detect and download generated files from Job pods before cleanup.
* Introduce  method in JobExecutor for file retrieval.
* Update ExecutionResult model to include  attribute.
* Implement  method in ExecutionServiceInterface for accessing pre-downloaded file content.
* Enhance orchestrator to utilize pre-downloaded content when container is unavailable.
* Add unit tests for new functionality and ensure proper handling of code files.

* style(runner, job_executor): format code for consistency

* refactor(execution): scope job file contents by session_id

* Change job file content storage to use a tuple of (session_id, path) for unique identification.
* Update related methods to accommodate session-based file content retrieval.
* Enhance unit tests to verify session-specific behavior for job file content management.