Add Socket.IO layer for real-time communication

[hussein-m-kandil]

Summary

This PR introduces real-time, bidirectional communication using Socket.IO to enable instant client updates. Clients are now notified immediately when chats are created, received/seen, updated, or deleted, improving responsiveness and user experience in a more professional yet efficient way.

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Key Features

Real-time Communication

• Integrated Socket.IO server alongside the existing HTTP API.
• Enabled bidirectional client–server communication for chat events.

Live Chat Updates

• Notify connected clients when chats are created, received/seen, updated, or deleted.
• Emit scoped events so only affected chat participants receive updates.

Notes

• This PR adds real-time capabilities without changing existing REST contracts.
• Existing endpoints remain backward-compatible.
• Notifications are stateless; meant to only inform the client that it needs to update.