The function performed client-side filtering on top of listOrders
but was never called by any page. listPlayersByShop is kept as-is
since the backend has no dedicated shop players endpoint.
Rewrite store/notifications.ts to fetch via listNotifications
API and remove local generateId-based notification creation.
The store now acts as a simple cache with fetch/invalidate methods.
Header unread count reads from this API-backed cache.