Function pushHistory

app.js:1932–1939

()

}

function pushHistory() {
  if (historyLocked) return;
  const snap = deepCloneState();
  history = history.slice(0, historyIndex + 1);
  history.push(snap);
  historyIndex = history.length - 1;
  updateUndoRedoButtons();
}

function updateUndoRedoButtons() {
  undoBtn.disabled = historyIndex <= 0;