feat: Add HistoryManager for undo/redo functionality

frontend/src/history/HistoryManager.ts

@@ -0,0 +1,62 @@
+import * as Y from 'yjs';
+
+class HistoryManager {
+  private undoStack: Uint8Array[] = [];
+  private redoStack: Uint8Array[] = [];
+  private maxSize: number;
+  private doc: Y.Doc;
+
+  constructor(doc: Y.Doc, maxSize: number = 100) {
+    this.doc = doc;
+    this.maxSize = maxSize;
+  }
+
+  push(update: Uint8Array) {
+    this.undoStack.push(update);
+    if (this.undoStack.length > this.maxSize) {
+      this.undoStack.shift();
+    }
+    // Clear redo stack when new action is performed
+    this.redoStack = [];
+  }
+
+  undo() {
+    if (this.undoStack.length === 0) return false;
+    
+    const update = this.undoStack.pop();
+    if (update) {
+      // Apply inverse of the update
+      Y.applyUpdate(this.doc, Y.encodeStateAsUpdate(this.doc, Y.createRelativePositionFromJSON(Y.createRelativePositionFromType(update as any))));
+      this.redoStack.push(update);
+      return true;
+    }
+    return false;
+  }
+
+  redo() {
+    if (this.redoStack.length === 0) return false;
+    
+    const update = this.redoStack.pop();
+    if (update) {
+      Y.applyUpdate(this.doc, update);
+      this.undoStack.push(update);
+      return true;
+    }
+    return false;
+  }
+
+  canUndo(): boolean {
+    return this.undoStack.length > 0;
+  }
+
+  canRedo(): boolean {
+    return this.redoStack.length > 0;
+  }
+
+  clear() {
+    this.undoStack = [];
+    this.redoStack = [];
+  }
+}
+
+export default HistoryManager;