fix(ssr): avoid accessing localStorage during SSR initialization

- Initialize activeInterconnectNodeId with empty string
- Read from localStorage only in client-side
- Defer selected state initialization in NodeSwitcher to useEffect

web/src/api/index.ts

@@ -65,8 +65,16 @@ export interface MonitorStats {
     }[]
   }
 }
-export let activeInterconnectNodeId = localStorage.getItem('activeInterconnectNodeId') || ''
-export let activeInterconnectNodeName = localStorage.getItem('activeInterconnectNodeName') || ''
+
+// 初始化时使用空字符串，避免 SSR 时访问 localStorage
+export let activeInterconnectNodeId = ''
+export let activeInterconnectNodeName = ''
+
+// 在客户端初始化时从 localStorage 读取
+if (typeof window !== 'undefined') {
+  activeInterconnectNodeId = localStorage.getItem('activeInterconnectNodeId') || ''
+  activeInterconnectNodeName = localStorage.getItem('activeInterconnectNodeName') || ''
+}
 
 export function setActiveInterconnectNodeId(id: string, name?: string) {
   activeInterconnectNodeId = id

web/src/components/business/NodeSwitcher.tsx

@@ -13,7 +13,7 @@ import { cn } from '@/lib/utils'
 
 export function NodeSwitcher() {
   const [nodes, setNodes] = useState<InterconnectNode[]>([])
-  const [selected, setSelected] = useState(activeInterconnectNodeId || 'local')
+  const [selected, setSelected] = useState('local')
   const [isMaster, setIsMaster] = useState(false)
   const [open, setOpen] = useState(false)
   const [menuStyle, setMenuStyle] = useState<React.CSSProperties>({})
@@ -22,6 +22,8 @@ export function NodeSwitcher() {
 
   useEffect(() => {
     setMounted(true)
+    // 在客户端初始化时从 localStorage 读取选中的节点
+    setSelected(activeInterconnectNodeId || 'local')
   }, [])
 
   const fetchNodes = useCallback(async () => {