feat(client/nodes): 节点页刷新 — 下拉刷新 + 刷新按钮 + 进页刷新 + 10s 限流

- nodesProvider.refresh:10s 限流(下拉/按钮/进页多次触发只打一次远端);
  不清空当前列表(后台拉、好了再换,失败保留旧数据),避免进页/下拉闪空
- nodes_page:initState 进页自动刷一次;RefreshIndicator 下拉刷新(移动端);
  搜索框右侧 _RefreshButton 点击刷新(刷新中 spinner)
servers 页 golden 重生成(搜索行加按钮);CI 闸 golden 未动。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

client/lib/screens/nodes_page.dart

@@ -25,6 +25,23 @@ class NodesPage extends ConsumerStatefulWidget {
 
 class _NodesPageState extends ConsumerState<NodesPage> {
   String _q = '';
+  bool _refreshing = false;
+
+  @override
+  void initState() {
+    super.initState();
+    // 切到节点页自动刷新一次(受 nodesProvider 的 10s 限流)。
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (mounted) _refresh();
+    });
+  }
+
+  Future<void> _refresh() async {
+    if (_refreshing) return;
+    setState(() => _refreshing = true);
+    await ref.read(nodesProvider.notifier).refresh();
+    if (mounted) setState(() => _refreshing = false);
+  }
 
   void _pick(String code) {
     ref.read(selectedNodeCodeProvider.notifier).state = code;
@@ -49,18 +66,27 @@ class _NodesPageState extends ConsumerState<NodesPage> {
     final smart = selected == kSmartNodeCode;
 
     final smartCard = SmartSelectCard(t: t, selected: smart, onTap: () => _pick(kSmartNodeCode));
-    final search = _SearchBox(hint: t.searchPh, onChanged: (v) => setState(() => _q = v));
+    // 搜索框 + 刷新按钮(点击刷新);列表本身支持下拉刷新。
+    final searchRow = Row(children: [
+      Expanded(child: _SearchBox(hint: t.searchPh, onChanged: (v) => setState(() => _q = v))),
+      const SizedBox(width: 10),
+      _RefreshButton(refreshing: _refreshing, onTap: _refresh),
+    ]);
 
     if (widget.isWide) {
       // 对照 dapp.jsx DServers：padding 4/28、网格 gap 10。智能卡置顶（CLAUDE.md §5 规范，三端一致）。
-      return ListView(
-        padding: const EdgeInsets.fromLTRB(28, 4, 28, 24),
-        children: [
-          smartCard,
-          const SizedBox(height: 14),
-          ConstrainedBox(constraints: const BoxConstraints(maxWidth: 380), child: search),
-          const SizedBox(height: 14),
-          GridView.count(
+      return RefreshIndicator(
+        color: c.accent,
+        backgroundColor: c.surface,
+        onRefresh: _refresh,
+        child: ListView(
+          padding: const EdgeInsets.fromLTRB(28, 4, 28, 24),
+          children: [
+            smartCard,
+            const SizedBox(height: 14),
+            ConstrainedBox(constraints: const BoxConstraints(maxWidth: 440), child: searchRow),
+            const SizedBox(height: 14),
+            GridView.count(
             crossAxisCount: 2,
             shrinkWrap: true,
             physics: const NeverScrollableScrollPhysics(),
@@ -73,6 +99,7 @@ class _NodesPageState extends ConsumerState<NodesPage> {
             ],
           ),
         ],
+        ),
       );
     }
 
@@ -81,13 +108,17 @@ class _NodesPageState extends ConsumerState<NodesPage> {
       AppTopBar(brand: t.brand),
       PageTitle(title: t.chooseNode),
       Expanded(
-        child: ListView(
-          padding: const EdgeInsets.fromLTRB(20, 0, 20, 20),
-          children: [
-            smartCard,
-            const SizedBox(height: 12),
-            search,
-            const SizedBox(height: 12),
+        child: RefreshIndicator(
+          color: c.accent,
+          backgroundColor: c.surface,
+          onRefresh: _refresh,
+          child: ListView(
+            padding: const EdgeInsets.fromLTRB(20, 0, 20, 20),
+            children: [
+              smartCard,
+              const SizedBox(height: 12),
+              searchRow,
+              const SizedBox(height: 12),
             Container(
               decoration: BoxDecoration(
                 color: c.surface,
@@ -109,6 +140,7 @@ class _NodesPageState extends ConsumerState<NodesPage> {
               ]),
             ),
           ],
+          ),
         ),
       ),
     ]);
@@ -148,6 +180,35 @@ class _SearchBox extends StatelessWidget {
 }
 
 /// 宽屏双列网格中的节点块。
+/// 刷新按钮(搜索框右侧):点击刷新节点列表(受 10s 限流);刷新中显示 spinner。
+class _RefreshButton extends StatelessWidget {
+  const _RefreshButton({required this.refreshing, required this.onTap});
+  final bool refreshing;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final c = context.pangolin;
+    return Material(
+      color: c.bgSubtle,
+      borderRadius: BorderRadius.circular(PangolinRadius.md),
+      clipBehavior: Clip.antiAlias,
+      child: InkWell(
+        onTap: refreshing ? null : onTap,
+        child: SizedBox(
+          width: 44,
+          height: 44,
+          child: Center(
+            child: refreshing
+                ? SizedBox(width: 16, height: 16, child: CircularProgressIndicator(strokeWidth: 2, color: c.accent))
+                : Icon(PangolinIcons.refreshCw, size: 18, color: c.fg2),
+          ),
+        ),
+      ),
+    );
+  }
+}
+
 class _NodeGridTile extends StatelessWidget {
   const _NodeGridTile({required this.node, required this.lang, required this.active, required this.onTap});
   final Node node;