feat(nodes): bulk panel self-update with live online indicator

Adds the ability to update node panels to the latest release from the Nodes
page: select online, enabled nodes (checkboxes) and trigger their official
self-updater, or use the per-row Update action. A node whose reported panel
version trails the latest GitHub release is flagged with an 'update available'
tag (compared via lib/panel-version, mirroring the Go isNewerVersion).

Backend: Remote.UpdatePanel calls the node's existing
POST /panel/api/server/updatePanel; NodeService.UpdatePanels fans out over the
selected ids, skipping disabled/offline nodes with a per-node reason; exposed
as POST /panel/api/nodes/updatePanel (documented in endpoints.ts + openapi.json).

The bulk request sends a JSON body, so it sets Content-Type: application/json
explicitly — axios defaults POST to form-urlencoded, which made ShouldBindJSON
fail with 'invalid character i'.

Also reuses the clients-page online cue on the Nodes page: a pulsing green dot
plus green label for an online node. The .online-dot style moved to the shared
styles/utils.css so both pages load it.

Translations for all new node keys added across every language file.

frontend/src/pages/nodes/NodesPage.tsx

@@ -1,5 +1,6 @@
 import { useCallback, useEffect, useMemo, useState } from 'react';
 import { useTranslation } from 'react-i18next';
+import { useQuery } from '@tanstack/react-query';
 import { Card, Col, ConfigProvider, Layout, Modal, Row, Spin, Statistic, message } from 'antd';
 import {
   CheckCircleOutlined,
@@ -17,6 +18,8 @@ import AppSidebar from '@/layouts/AppSidebar';
 import NodeList from './NodeList';
 import NodeFormModal from './NodeFormModal';
 import { setMessageInstance } from '@/utils/messageBus';
+import { HttpUtil } from '@/utils';
+import type { PanelUpdateInfo } from '../index/PanelUpdateModal';
 
 export default function NodesPage() {
   const { t } = useTranslation();
@@ -27,11 +30,21 @@ export default function NodesPage() {
   useEffect(() => { setMessageInstance(messageApi); }, [messageApi]);
 
   const { nodes, loading, fetched, totals } = useNodesQuery();
-  const { create, update, remove, setEnable, testConnection, probe } = useNodeMutations();
+  const { create, update, remove, setEnable, testConnection, probe, updatePanels } = useNodeMutations();
+
+  const { data: latestVersion = '' } = useQuery({
+    queryKey: ['server', 'panelUpdateInfo'],
+    queryFn: async () => {
+      const msg = await HttpUtil.get<PanelUpdateInfo>('/panel/api/server/getPanelUpdateInfo');
+      return msg?.obj?.latestVersion || '';
+    },
+    staleTime: 5 * 60 * 1000,
+  });
 
   const [formOpen, setFormOpen] = useState(false);
   const [formMode, setFormMode] = useState<'add' | 'edit'>('add');
   const [formNode, setFormNode] = useState<NodeRecord | null>(null);
+  const [selectedIds, setSelectedIds] = useState<number[]>([]);
 
   const onAdd = useCallback(() => {
     setFormMode('add');
@@ -81,6 +94,52 @@ export default function NodesPage() {
     await setEnable(node.id, next);
   }, [setEnable]);
 
+  const runUpdate = useCallback(async (ids: number[]) => {
+    const msg = await updatePanels(ids);
+    if (!msg?.success) {
+      messageApi.error(msg?.msg || t('somethingWentWrong'));
+      return;
+    }
+    const results = msg.obj ?? [];
+    const ok = results.filter((r) => r.ok).length;
+    const failed = results.length - ok;
+    if (failed === 0) {
+      messageApi.success(t('pages.nodes.toasts.updateStarted'));
+    } else {
+      const firstError = results.find((r) => !r.ok)?.error ?? '';
+      const base = t('pages.nodes.toasts.updateResult', { ok, failed });
+      messageApi.warning(firstError ? `${base} — ${firstError}` : base);
+    }
+    setSelectedIds([]);
+  }, [updatePanels, messageApi, t]);
+
+  const onUpdateNode = useCallback((node: NodeRecord) => {
+    modal.confirm({
+      title: t('pages.nodes.updateConfirmTitle', { count: 1 }),
+      content: t('pages.nodes.updateConfirmContent'),
+      okText: t('update'),
+      cancelText: t('cancel'),
+      onOk: () => runUpdate([node.id]),
+    });
+  }, [modal, t, runUpdate]);
+
+  const onUpdateSelected = useCallback(() => {
+    const eligible = nodes
+      .filter((n) => selectedIds.includes(n.id) && n.enable && n.status === 'online')
+      .map((n) => n.id);
+    if (eligible.length === 0) {
+      messageApi.warning(t('pages.nodes.toasts.updateNoneEligible'));
+      return;
+    }
+    modal.confirm({
+      title: t('pages.nodes.updateConfirmTitle', { count: eligible.length }),
+      content: t('pages.nodes.updateConfirmContent'),
+      okText: t('update'),
+      cancelText: t('cancel'),
+      onOk: () => runUpdate(eligible),
+    });
+  }, [modal, t, nodes, selectedIds, runUpdate, messageApi]);
+
   const pageClass = useMemo(() => {
     const classes = ['nodes-page'];
     if (isDark) classes.push('is-dark');
@@ -142,11 +201,16 @@ export default function NodesPage() {
                       nodes={nodes}
                       loading={loading}
                       isMobile={isMobile}
+                      latestVersion={latestVersion}
+                      selectedIds={selectedIds}
+                      onSelectionChange={setSelectedIds}
                       onAdd={onAdd}
                       onEdit={onEdit}
                       onDelete={onDelete}
                       onProbe={onProbe}
                       onToggleEnable={onToggleEnable}
+                      onUpdateNode={onUpdateNode}
+                      onUpdateSelected={onUpdateSelected}
                     />
                   </Col>
                 </Row>