fix(#145): dashboard notification widget shows all recent notifications

- Add type-only filter to notification repo/service (previously only
  worked with type+read=false together)
- Dashboard widget now fetches all recent notifications (mentions +
  replies, both read and unread) instead of unread mentions only
- Update component heading and show type label per row

Root cause: Berit's mentions were read=true, so the unread-only filter
returned 0 results. The recent docs widget had no REVIEWED documents
because 'marking ready' sets metadata_complete, not status=REVIEWED.
Recent docs now shows all uploads without a status filter.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/src/main/java/org/raddatz/familienarchiv/repository/NotificationRepository.java

@@ -15,6 +15,9 @@ public interface NotificationRepository extends JpaRepository<Notification, UUID
 
     Page<Notification> findByRecipientIdOrderByCreatedAtDesc(UUID recipientId, Pageable pageable);
 
+    Page<Notification> findByRecipientIdAndTypeOrderByCreatedAtDesc(
+            UUID recipientId, NotificationType type, Pageable pageable);
+
     Page<Notification> findByRecipientIdAndTypeAndReadFalseOrderByCreatedAtDesc(
             UUID recipientId, NotificationType type, Pageable pageable);
 

backend/src/main/java/org/raddatz/familienarchiv/service/NotificationService.java

@@ -98,6 +98,10 @@ public class NotificationService {
             return notificationRepository.findByRecipientIdAndTypeAndReadFalseOrderByCreatedAtDesc(userId, type, pageable)
                     .map(this::toDTO);
         }
+        if (type != null) {
+            return notificationRepository.findByRecipientIdAndTypeOrderByCreatedAtDesc(userId, type, pageable)
+                    .map(this::toDTO);
+        }
         return notificationRepository.findByRecipientIdOrderByCreatedAtDesc(userId, pageable)
                 .map(this::toDTO);
     }