fix: hide completion prompt after confirmation

assets/styles.css

@@ -276,6 +276,7 @@ button { cursor: pointer; }
 .attachments h3 { margin: 0 0 8px; font-size: 14px; }
 .attachment-item { padding: 7px 0; color: #555; font-size: 13px; }
 .attachments a { color: var(--navy); text-decoration: underline; }
+.completion-notice[hidden], .completion-done-notice[hidden] { display: none; }
 .completion-notice { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin: 20px 22px 0; padding: 15px 17px; border: 1px solid #f0c45c; background: #fff9e8; color: #5b4500; }
 .completion-notice strong { display: block; margin-bottom: 4px; }
 .completion-notice p { margin: 0; font-size: 13px; }