feat(packages): add settings menu (#1615)

Co-authored-by: Cursor <cursoragent@cursor.com>

packages/html/src/ui/command-for.ts

@@ -0,0 +1,12 @@
+/** Toggle a popup host linked via `commandfor` (menu, popover, etc.). */
+export function toggleCommandTarget(host: HTMLElement, commandfor: string): void {
+  const root = host.getRootNode() as Document | ShadowRoot;
+  const target =
+    ('getElementById' in root ? root.getElementById(commandfor) : null) ??
+    root.querySelector<HTMLElement>(`#${CSS.escape(commandfor)}`);
+
+  if (!target || !('open' in target)) return;
+
+  const popup = target as { open: boolean };
+  popup.open = !popup.open;
+}