fix: shutdown manager for handling cleanup tasks

[dhirajsuthar781]

This PR introduces a centralized ShutdownManager to handle graceful shutdown of the application and all its resources (MongoDB, PostgreSQL, RabbitMQ, HTTP server).

Previously, shutdown logic was tightly coupled within the startServer() function, making it harder to scale, maintain, and extend. This refactor extracts that logic into a reusable, production-grade lifecycle component.

What’s Changed

config/shutdown.js

Responsibilities:

• Register cleanup tasks dynamically
• Listen to system signals (SIGINT, SIGTERM)
• Handle uncaughtException and unhandledRejection
• Execute shutdown tasks in a controlled manner
• Enforce timeout-based forced shutdown fallback

Refactored Server Bootstrap

• Removed inline graceful shutdown logic from startServer()
• Integrated ShutdownManager for lifecycle handling

Author

Suthar Dhiraj
Full Stack Developer

• Focus on Event-driven system, observability, microservices, devOps

[rahulnikam2002]

Great work @dhirajsuthar781 - Glad you are solving real problems!
I'll review and merge this.