Implement and test real-time notifications (Socket.io)

[Nathydre]

Problem

The backend has 'SocketServer.ts', 'RealTimeService.ts', and 'RealTimeNotifications.tsx' but the real-time notification system needs comprehensive testing.

Acceptance Criteria

• Audit Socket.io implementation
• Add connection authentication
• Test event broadcasting
• Add room-based notifications
• Test reconnection handling
• Add notification persistence for offline users
• Write integration tests for real-time features

[od-hunter]

Hi can I be assigned this issue please?

[grantfox-oss]

🦊 GrantFox — @od-hunter has been assigned to this issue as part of the Third Campaign campaign!

Next steps:

1. Open a Pull Request referencing this issue (e.g., Closes #470)
2. Your PR will be reviewed by the nathydre21 maintainers

Good luck! Track your progress on GrantFox.

[grantfox-oss]

🎉 This issue has been marked as completed on GrantFox as part of the Third Campaign campaign!

@od-hunter's PR #484 was approved and merged by @Nathydre.

🏆 @od-hunter: You earned 40 FoxPoints for this contribution! Your current tier: Builder (1,148 total points). Track your full progress on GrantFox.

👏 Great work, @od-hunter! Keep contributing to nathydre21.