feat: centralize notification reconciliation workflow

[ash1shkumar]

📝 Description

This PR improves notification state management by introducing a centralized notification reconciliation workflow and reusable notification helpers.

Previously, notification updates such as individual read actions, bulk read operations, and unread count calculations were handled through localized state mutations. As notification volume and realtime event activity increase, maintaining consistent notification state becomes more challenging and can lead to synchronization issues.

Changes Implemented

• Added reusable notification reconciliation helper
• Added centralized unread count calculation helper
• Standardized notification state update workflows
• Reduced duplicated notification mutation logic
• Improved consistency across notification lifecycle operations
• Centralized notification reconciliation behavior
• Improved maintainability of notification state management

Benefits

• Improved notification reliability
• More consistent unread count handling
• Reduced stale state propagation risk
• Better support for concurrent notification updates
• Cleaner separation of notification lifecycle responsibilities
• Improved maintainability and scalability
• Easier future notification feature development

🎯 Type of Change

• Refactoring
• Performance Improvement
• Maintainability Enhancement

✅ Testing

• Verified notification panel opens and closes correctly
• Verified unread notification count updates correctly
• Verified individual notifications can be marked as read
• Verified "Mark all as read" functionality works correctly
• Verified notification navigation behavior remains unchanged
• Verified notification badge count remains accurate
• Verified notification rendering remains unchanged
• Verified empty notification state continues to function properly
• Verified no UI regressions after refactoring
• Verified notification state updates remain synchronized

Fixes #205

Expected Labels

level3 NSoC'26

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