RM-10: Replace close request queue with precise scheduler

[biast12]

RM-10

Description

Replace the queue-based close request system with a timer-based scheduler that fires requests at their exact close_at time. This eliminates the sweep interval delay and improves precision. The scheduler uses a reconciliation pattern to arm, re-arm, and cancel timers based on the current database state, handling cases where requests are denied, closed, excluded, or rescheduled. Also added a default sweep time of 1 second to the config.

Type of Change

• Bug fix
• New feature
• Breaking change
• Improvement

Testing

Open a few tickets and send a close request for each of them, with some space in between them.

Checklist

• My code follows the style of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works