Support passing Async::Semaphore as the parent task for Async::Job::Processor::Redis::Server

[shaokun]

Summary

This PR refactors the Async::Job::Processor::Redis::Server to support passing an Async::Semaphore as the parent task. The change restructures the concurrency model by moving job processing into a separate async task wrapper, allowing for better control over concurrent job execution through semaphores.

Key Changes:

• Refactored task hierarchy: The main server loop now runs in a separate async task, with each job dequeue operation wrapped in its own transient task with the semaphore/parent as its parent
• Simplified dequeue method: Removed the parent parameter from dequeue - job processing logic is now synchronous within its async wrapper
• Better concurrency control: Enables limiting concurrent job processing by passing a semaphore with a specific limit

This change maintains backward compatibility while enabling use cases where you want to limit the number of jobs processed concurrently (e.g., rate limiting, resource management).

Types of Changes

• New feature.
• Maintenance.

Contribution

• I added tests for my changes.
• I tested my changes locally.
• I agree to the Developer's Certificate of Origin 1.1.