grid support (1st iteration) (#1788)

Co-authored-by: dwelle <luzar.david@gmail.com>

src/appState.ts

@@ -53,6 +53,7 @@ export const getDefaultAppState = (): AppState => {
     shouldCacheIgnoreZoom: false,
     showShortcutsDialog: false,
     zenModeEnabled: false,
+    gridSize: null,
     editingGroupId: null,
     selectedGroupIds: {},
   };
@@ -81,5 +82,6 @@ export const clearAppStateForLocalStorage = (appState: AppState) => {
 export const cleanAppStateForExport = (appState: AppState) => {
   return {
     viewBackgroundColor: appState.viewBackgroundColor,
+    gridSize: appState.gridSize,
   };
 };