* display notification bell icon beside URL bar
* notification model
* persist received notifications
* Refresh notification list. Add is_read flag and display unread count.
* Hide notifications when opening the navigatinon drawer. Open selected notification item before hiding the list.
* update local store with remote notifications
* use card view for notification items
* make notification cards clickable
* handle comment hash
* fix remote notifications not loading. fix comment scroll.
* Improve in-app comment notification linking. Add icons.