Hide copy button when user message has no text content [codecane]

Skip rendering the copy button for messages with empty content
(e.g., image-only messages) since there is nothing to copy.

Author: brandonkachen

cli/src/components/blocks/user-content-copy.tsx

@@ -35,7 +35,9 @@ export const UserContentWithCopyButton = memo(
       ? trimTrailingNewlines(content)
       : content.trim()
 
-    if (!showCopyButton) {
+    const hasContent = normalizedContent.length > 0
+
+    if (!showCopyButton || !hasContent) {
       return (
         <text
           key={`message-content-${messageId}`}