Preserve QExcell worksheet zoom in XLSX

src/types.ts

@@ -25,6 +25,7 @@ export interface Sheet {
   columnWidths?: Record<string, number>;
   rowHeights?: Record<string, number>;
   showGridLines?: boolean;
+  zoomScale?: number;
   cells: Record<string, string>;
   mergedCells?: MergedCellRange[];
   hyperlinks?: Record<string, string>;