fix(NodeSwitcher): avoid SSR hydration error by deferring portal creation

web/src/components/business/NodeSwitcher.tsx

@@ -17,8 +17,13 @@ export function NodeSwitcher() {
   const [isMaster, setIsMaster] = useState(false)
   const [open, setOpen] = useState(false)
   const [menuStyle, setMenuStyle] = useState<React.CSSProperties>({})
+  const [mounted, setMounted] = useState(false)
   const buttonRef = useRef<HTMLButtonElement>(null)
 
+  useEffect(() => {
+    setMounted(true)
+  }, [])
+
   const fetchNodes = useCallback(async () => {
     try {
       const res = await getNodes()
@@ -157,6 +162,7 @@ export function NodeSwitcher() {
       </button>
 
       {open &&
+        mounted &&
         createPortal(
           <div className="ui-select-menu" style={menuStyle}>
             {allOptions.map((opt) => (