add csound minimal example

packages/csound/example/counter.js

@@ -0,0 +1,9 @@
+export function setupCounter(element) {
+  let counter = 0
+  const setCounter = (count) => {
+    counter = count
+    element.innerHTML = `count is ${counter}`
+  }
+  element.addEventListener('click', () => setCounter(counter + 1))
+  setCounter(0)
+}