Restore truncated overflow-page comment dropped by the finish diff (#158)

backend/internal/web/admin_series.go

@@ -570,6 +570,8 @@ func (h *Handler) seriesListView(r *http.Request) (seriesListView, error) {
 	if err != nil {
 		return seriesListView{}, err
 	}
+	// A page past the end is not an empty list: the store's window count runs
+	// over the rows the result set carries, so an overflow page reports zero
 	// rows and zero total, and the list re-reads at page 1 to know the truth.
 	if len(data.Rows) == 0 && page > 1 {
 		page = 1