fix: issue #20 cmd-J panel tab strip visibility and output panel parity

assets/js/utils/clipboard.js

@@ -0,0 +1,27 @@
+// Copies text to the system clipboard, mirroring the old app's behavior:
+// navigator.clipboard when available, with a hidden-textarea fallback for
+// webviews that lack the async clipboard API.
+export const copyTextToClipboard = async (text) => {
+  if (typeof navigator !== "undefined" && navigator.clipboard && typeof navigator.clipboard.writeText === "function") {
+    await navigator.clipboard.writeText(text);
+    return;
+  }
+
+  if (typeof document === "undefined" || typeof document.createElement !== "function") {
+    return;
+  }
+
+  const textArea = document.createElement("textarea");
+  textArea.value = text;
+  textArea.setAttribute("readonly", "");
+  textArea.style.position = "absolute";
+  textArea.style.left = "-9999px";
+  document.body.appendChild(textArea);
+  textArea.select();
+
+  if (typeof document.execCommand === "function") {
+    document.execCommand("copy");
+  }
+
+  document.body.removeChild(textArea);
+};