Add redis (Cache + queue)

Integrate Redis for caching and job queueing.

Requirements:

• Setup Redis instance (local or cloud)
• Create cache service for frequently accessed data (user profiles, groups, etc.)
• Implement session management with Redis
• Add job queue functionality using Bull or similar
• Configure cache invalidation strategies
• Add monitoring and health checks for Redis

Deliverables:

• Redis connection service
• Cache service module with get/set/delete operations
• Session management implementation
• Job queue setup and handlers
• Redis configuration and documentation