Delete Batch

Ids to delete in one request.

Deleting is PERMANENT — there is no dismissed/archived state for a notification, and the web's own Dismiss button is a hard delete too. Idempotent all the same: ids that do not exist or belong to someone else are silently ignored, so a retried batch is a no-op rather than an error.

The caller's own unread count, and nothing else.

The same single field as :class:NotificationBatchReadOut, for the same reason and then one more.

The shared reason: a per-id result, a matched count, or a list of ids that did not apply would report which SUBMITTED ids turned out to be real and the caller's — an enumeration oracle a hundred guesses at a time, which is exactly what DELETE /{id}'s uniform 204 exists to deny.

The extra one: a remaining-TOTAL count would be a strictly better oracle here than unread_count is. Deleting leaves no trace in the unread count when the notification was already read, so an attacker probing with read ids learns nothing from it — but a total would move for every id that was real and theirs, read or not. It is the caller's own aggregate and looks harmless, which is precisely why it is worth not returning.