21. Add TodosDifficulty: easy | Stack: react | XP: 25Problem Description## Step 1: Add Todos The skeleton is in place. Wire up the input and button so the user can add todos to the list. ### Requirements 1. Track the input value in state 2. Clicking **Add** appends the typed text as a new `<li>` in `<ul id="todos">` 3. After adding, **clear the input** 4. Ignore empty/whitespace-only submissions 5. Each `<li>` should have a stable `key` (use `Date.now()` or a counter — anything but the array index)