feat: import review step + admin notifications

- Import page: add file upload with review step before committing
- Backend: add analyze endpoint to preview chapters before import
- Add notifications collection + API for admin alerts
- Add bell icon in header with notification dropdown (admin only)
- Runner creates notification on import completion
- Notifications link to /admin/import for easy review

backend/internal/storage/store.go

@@ -667,6 +667,46 @@ func (s *Store) CreateImportTask(ctx context.Context, slug, title, fileType, obj
 	return rec.ID, nil
 }
 
+// CreateNotification creates a notification record in PocketBase.
+func (s *Store) CreateNotification(ctx context.Context, userID, title, message, link string) error {
+	payload := map[string]any{
+		"user_id":  userID,
+		"title":     title,
+		"message":  message,
+		"link":     link,
+		"read":     false,
+		"created":  time.Now().UTC().Format(time.RFC3339),
+	}
+	return s.pb.post(ctx, "/api/collections/notifications/records", payload, nil)
+}
+
+// ListNotifications returns notifications for a user.
+func (s *Store) ListNotifications(ctx context.Context, userID string, limit int) ([]map[string]any, error) {
+	filter := fmt.Sprintf("user_id='%s'", userID)
+	items, err := s.pb.listAll(ctx, "notifications", filter, "-created")
+	if err != nil {
+		return nil, err
+	}
+	// Parse each json.RawMessage into a map
+	results := make([]map[string]any, 0, len(items))
+	for _, raw := range items {
+		var m map[string]any
+		if json.Unmarshal(raw, &m) == nil {
+			results = append(results, m)
+		}
+	}
+	if limit > 0 && len(results) > limit {
+		results = results[:limit]
+	}
+	return results, nil
+}
+
+// MarkNotificationRead marks a notification as read.
+func (s *Store) MarkNotificationRead(ctx context.Context, id string) error {
+	return s.pb.patch(ctx, fmt.Sprintf("/api/collections/notifications/records/%s", id),
+		map[string]any{"read": true})
+}
+
 func (s *Store) CancelTask(ctx context.Context, id string) error {
 	// Try scraping_tasks first, then audio_jobs, then translation_jobs.
 	if err := s.pb.patch(ctx, fmt.Sprintf("/api/collections/scraping_tasks/records/%s", id),