Add persistent history stacks

src/frontend/types.ts

@@ -6,6 +6,15 @@ export interface ProjectDto {
   currentRevision: number;
 }
 
+export interface ProjectHistoryStateDto {
+  projectId: string;
+  currentRevision: number;
+  undoDepth: number;
+  redoDepth: number;
+  undoChangeSetId: string | null;
+  redoChangeSetId: string | null;
+}
+
 export interface DistributionBoardDto {
   id: string;
   projectId: string;