Fix customer header outside-click handler for DOM event typing.

Use Event instead of React MouseEvent so document listeners typecheck in production builds.

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

apps/customer/src/components/Header.tsx

@@ -89,8 +89,13 @@ export function Header({
   useEffect(() => {
     if (!menuOpen) return
 
-    function handleClickOutside(e: MouseEvent) {
-      if (menuRef.current && !menuRef.current.contains(e.target as Node)) {
+    function handleClickOutside(e: Event) {
+      const target = e.target
+      if (
+        target instanceof Node &&
+        menuRef.current &&
+        !menuRef.current.contains(target)
+      ) {
         setMenuOpen(false)
       }
     }