Added FOCUS-55933 - heartbeat message

This update improves system stability and cron processing by ensuring that cron job output stored in cron_history reflects only the actual job results, eliminating cases where (no output) was incorrectly appended. It also enhances cleanup of stalled or zombie tasks by automatically removing processes that fail to exit after 24 hours, while maintaining the existing 4-hour cleanup for completed tasks. Additionally, task monitoring has been refined to prevent false disconnection errors, allowing long-running processes that complete successfully to return properly without triggering exceptions.