feat(one_shot): some deno boilerplate

examples/one_shot/islands/Counter.tsx

@@ -0,0 +1,17 @@
+import { useState } from "preact/hooks";
+import { Button } from "../components/Button.tsx";
+
+interface CounterProps {
+  start: number;
+}
+
+export default function Counter(props: CounterProps) {
+  const [count, setCount] = useState(props.start);
+  return (
+    <div class="flex gap-2 w-full">
+      <p class="flex-grow-1 font-bold text-xl">{count}</p>
+      <Button onClick={() => setCount(count - 1)}>-1</Button>
+      <Button onClick={() => setCount(count + 1)}>+1</Button>
+    </div>
+  );
+}