Build notification and communication system

[b0ase]

Description

Create comprehensive notification system for user activities.

Tasks

• Implement email notifications
• Add in-app notifications
• Create webhook system
• Build notification preferences
• Add real-time updates via WebSocket
• Implement SMS notifications (optional)
• Create notification history
• Add notification templates
• Build admin broadcast system

References

• Header bar includes notifications placeholder
• Real-time updates needed for uploads

Priority: Low