[UIPKGE] Header-grade notifications panel. Slot-trigger Popover the consumer wraps around their own Bell button. Filter tabs (All/Unread), Today/Earlier groups, category-coloured accent bars, hover-dismiss, mark-all-read, slide-in animation. Slot receives `unreadCount` so the trigger can show a badge.
pnpm dlx shadcn@latest add "https://registry.directory/r/uday-a/notifications-popover.json"