Refactor: Standardize string usage and improve connection handling in queue management

Commit notes

This commit includes several improvements to the queue management system:

- Updated string literals to use double quotes consistently across the codebase. - Enhanced the handling of Redis connections by ensuring each worker has its own dedicated connection for blocking operations, improving reliability during job processing. - Added error handling for connection issues and implemented a cleanup mechanism for stale connections. - Improved job status management and logging for better traceability during job execution.

These changes aim to enhance code readability, maintainability, and the overall robustness of the queue system.