ISSUE 4: add redo functionality

src/components/DockBuilder/DockBuilder.jsx

@@ -501,7 +501,18 @@ export const DockBuilder = () => {
   }, [editorMemo]);
 
   const onRedoClick = useCallback(() => {
-    // TODO: Redo
+    const redoResult = stack.redo();
+    if (redoResult && redoResult.currentState) {
+      // currentState is an array, get the first element
+      const state = Array.isArray(redoResult.currentState)
+        ? redoResult.currentState[0]
+        : redoResult.currentState;
+      if (state) {
+        editorMemo.loadFromJSON(state, () => {
+          editorMemo.renderAll();
+        });
+      }
+    }
   }, [editorMemo]);
 
   const onPrintScreen = useCallback(() => {