FEATURE REQUEST: Centralized Notification Centre

### Is your feature request related to a problem?

- [x] Yes, it is related to a problem

### Describe the feature you'd like

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## 🌟 Feature Description
Implement a Notification Centre that provides users with a centralized, interactive space to view, manage, and act on all their notifications.

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## 🔍 Problem Statement
A Notification Centre is a standard feature in modern platforms, providing users with a single place to receive timely updates, alerts, and actionable information. Without it, users may miss important events such as new messages, collaboration invites, campaign updates, or system announcements.
Having a robust notification system not only improves user engagement and satisfaction but also lays the foundation for future features—such as real-time collaboration, workflow automation, and advanced user interactions—by ensuring users are always informed and can act promptly on relevant events.

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## 🎯 Expected Outcome
- Users can access a dedicated Notification Centre from the main navigation.
- All notifications (unread and recent read) are displayed in a clear, organized list.
- Users can select and delete notifications (single or bulk).
- Clicking a notification opens a dialog with its details (title, content, timestamp, and category icon).
- Read notifications are visually distinct (duller) from unread ones.
- Real-time updates for new notifications.
- Notification badge in the navigation shows the count of unread notifications.

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## 📋 Additional Context
- Use Supabase Realtime for instant updates.
- Ensure notifications are only visible to the intended user (secure API).
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### Record

- [x] I agree to follow this project's Code of Conduct
- [x] I want to work on implementing this feature