feat(admin-frontend): 新增系统与订阅管理后台页面

扩展管理端侧边栏与路由，新增系统配置真实页面、订阅套餐
管理页、节点管理页及多个结构化占位页

补齐前端 API、类型与工具层，并增强仪表盘刷新、趋势切换、
失败作业详情与流量排行 limit 联动能力

同步后端 traffic rank limit 支持与知识库归档、设计约束、
验证配置及视觉验收产物

admin-frontend/src/utils/nodes.ts

@@ -0,0 +1,151 @@
+import type { AdminNodeItem } from '@/types/api'
+
+export interface NodeStatusMeta {
+  label: string
+  dotClass: 'online' | 'pending' | 'offline' | 'disabled'
+  tagType: 'success' | 'warning' | 'danger' | 'info'
+}
+
+const NODE_TYPE_LABELS: Record<string, string> = {
+  shadowsocks: 'Shadowsocks',
+  trojan: 'Trojan',
+  vmess: 'VMess',
+  vless: 'VLESS',
+  hysteria: 'Hysteria 2',
+  tuic: 'TUIC',
+  anytls: 'AnyTLS',
+  socks: 'SOCKS',
+  http: 'HTTP',
+  naive: 'Naive',
+  mieru: 'Mieru',
+}
+
+function normalizeText(value: unknown): string {
+  return String(value ?? '').trim().toLowerCase()
+}
+
+export function getNodeTypeLabel(type: string): string {
+  const normalized = normalizeText(type)
+  return NODE_TYPE_LABELS[normalized] ?? String(type || '未知协议').toUpperCase()
+}
+
+export function getNodeStatusMeta(node: AdminNodeItem): NodeStatusMeta {
+  if (node.enabled === false) {
+    return {
+      label: '已停用',
+      dotClass: 'disabled',
+      tagType: 'info',
+    }
+  }
+
+  if (node.available_status === 2) {
+    return {
+      label: '在线',
+      dotClass: 'online',
+      tagType: 'success',
+    }
+  }
+
+  if (node.available_status === 1) {
+    return {
+      label: '待同步',
+      dotClass: 'pending',
+      tagType: 'warning',
+    }
+  }
+
+  return {
+    label: '离线',
+    dotClass: 'offline',
+    tagType: 'danger',
+  }
+}
+
+export function getNodeIdLabel(node: AdminNodeItem): string {
+  return node.parent_id ? `${node.id} → ${node.parent_id}` : String(node.id)
+}
+
+export function getNodeAddress(node: AdminNodeItem): { primary: string; secondary: string } {
+  const host = node.host || '--'
+  const publicPort = node.server_port ?? node.port ?? '--'
+  const innerPort = node.port ?? node.server_port ?? '--'
+
+  return {
+    primary: `${host}:${publicPort}`,
+    secondary: `内部端口 ${innerPort}`,
+  }
+}
+
+export function formatNodeRate(rate?: number | null): string {
+  const normalized = Number.isFinite(Number(rate)) ? Number(rate) : 1
+  return `${normalized.toFixed(2)} x`
+}
+
+export function getNodeGroupNames(node: AdminNodeItem): string[] {
+  return (node.groups ?? [])
+    .map((group) => group.name)
+    .filter(Boolean)
+}
+
+export function buildNodeTypeOptions(nodes: AdminNodeItem[]): Array<{ label: string; value: string }> {
+  const uniqueTypes = [...new Set(nodes.map((node) => normalizeText(node.type)).filter(Boolean))]
+  return uniqueTypes.map((value) => ({
+    value,
+    label: getNodeTypeLabel(value),
+  }))
+}
+
+function buildNodeSearchText(node: AdminNodeItem): string {
+  return [
+    node.id,
+    node.parent_id,
+    node.name,
+    node.host,
+    node.port,
+    node.server_port,
+    getNodeTypeLabel(node.type),
+    ...getNodeGroupNames(node),
+  ]
+    .map((item) => String(item ?? '').trim())
+    .filter(Boolean)
+    .join(' ')
+    .toLowerCase()
+}
+
+export function filterNodes(
+  nodes: AdminNodeItem[],
+  keyword: string,
+  typeFilter: string,
+  groupFilter: string,
+): AdminNodeItem[] {
+  const normalizedKeyword = normalizeText(keyword)
+  const normalizedType = normalizeText(typeFilter)
+  const normalizedGroup = normalizeText(groupFilter)
+
+  return nodes.filter((node) => {
+    if (normalizedKeyword && !buildNodeSearchText(node).includes(normalizedKeyword)) {
+      return false
+    }
+
+    if (normalizedType !== '' && normalizedType !== 'all' && normalizeText(node.type) !== normalizedType) {
+      return false
+    }
+
+    if (normalizedGroup !== '' && normalizedGroup !== 'all') {
+      const belongsToGroup = (node.groups ?? []).some((group) => String(group.id) === normalizedGroup)
+      if (!belongsToGroup) {
+        return false
+      }
+    }
+
+    return true
+  })
+}
+
+export function countOnlineNodes(nodes: AdminNodeItem[]): number {
+  return nodes.filter((node) => getNodeStatusMeta(node).dotClass === 'online').length
+}
+
+export function countVisibleNodes(nodes: AdminNodeItem[]): number {
+  return nodes.filter((node) => Boolean(node.show)).length
+}