Add a clipboard controller and wire up the copy button

app/javascript/controllers/clipboard_controller.js

@@ -0,0 +1,16 @@
+import { Controller } from "@hotwired/stimulus"
+
+export default class extends Controller {
+  static targets = ["source", "trigger"]
+
+  copy (event) {
+    event.preventDefault();
+    navigator.clipboard.writeText(this.sourceTarget.value);
+    this.triggerTarget.querySelector('.content-initial').classList.add('hidden');
+    this.triggerTarget.querySelector('.content-active').classList.remove('hidden');
+    setTimeout(() => {
+      this.triggerTarget.querySelector('.content-initial').classList.remove('hidden');
+      this.triggerTarget.querySelector('.content-active').classList.add('hidden');
+    }, 2000)
+  }
+}