What are React Hooks and why were they introduced? React Hooks क्या हैं और क्यों introduce किए गए?

// Hooks allow functional components to have state and lifecycle
// Before Hooks: only class components could have state/lifecycle
// After Hooks: functional components became powerful

// useState - add state to functional components
const [count, setCount] = useState(0);

// useEffect - handle side effects
useEffect(() => {
  document.title = `Count: ${count}`;
}, [count]);

// useContext - access context
const theme = useContext(ThemeContext);

// useReducer - complex state management
const [state, dispatch] = useReducer(reducer, initialState);