feat: use input type number for counter

islands/Counter.tsx

@@ -18,6 +18,7 @@ export default function Counter(props: CounterProps) {
       </Button>
       <input
         class="text-3xl bg-transparent inline text-center -mx-4"
+        type="number"
         size={props.count.toString().length}
         value={props.count}
         onInput={(ev) => props.count.value = ev.target?.value}