refactor(frontend): API 子模块化、大组件拆分与 TanStack Query hooks

P1: kubernetes/system API 拆为子目录模块，导出工具下沉到 lib/export-utils，
    http 统一 buildApiUrl/getWsBase；HostMonitor、DeploymentEdit* 拆至子组件。

P2: 新增 hooks/api（queryKeys、useTerminalSessions、useHostMonitor），
    TerminalSessionsTab 与 HostMonitor 接入 TanStack Query。

P3: 保留 services/api 路径，未迁移至 api/ 目录。

frontend/src/hooks/api/queryKeys.ts

@@ -0,0 +1,11 @@
+// TanStack Query key 工厂 — 统一缓存键 // Logan.Li
+
+export const queryKeys = {
+  terminalSessions: (params?: Record<string, unknown>) => ['terminal-sessions', params] as const,
+  hostMonitor: {
+    hosts: () => ['host-monitor', 'hosts'] as const,
+    history: (hostname: string, hours: number) => ['host-monitor', 'history', hostname, hours] as const,
+    probes: (hostname: string) => ['host-monitor', 'probes', hostname] as const,
+    portPolicy: (hostname: string) => ['host-monitor', 'port-policy', hostname] as const,
+  },
+};

frontend/src/hooks/api/useHostMonitor.ts

@@ -0,0 +1,66 @@
+// 主机监控数据 — TanStack Query // Logan.Li
+
+import { useQuery } from '@tanstack/react-query';
+import { agentApi } from '@/services/api';
+import { queryKeys } from './queryKeys';
+
+function unwrapList<T>(data: unknown): T[] {
+  if (Array.isArray(data)) return data;
+  if (data && typeof data === 'object') {
+    const obj = data as Record<string, unknown>;
+    if (Array.isArray(obj.list)) return obj.list as T[];
+    if (Array.isArray(obj.data)) return obj.data as T[];
+  }
+  return [];
+}
+
+export function useHostList() {
+  return useQuery({
+    queryKey: queryKeys.hostMonitor.hosts(),
+    queryFn: async () => {
+      const data = await agentApi.getLatest();
+      return unwrapList<Record<string, unknown>>(data);
+    },
+    staleTime: 30_000,
+  });
+}
+
+export function useHostHistory(hostname: string, hours: number) {
+  return useQuery({
+    queryKey: queryKeys.hostMonitor.history(hostname, hours),
+    queryFn: async () => {
+      if (!hostname) return [];
+      const data = await agentApi.getHistory(hostname, hours);
+      return unwrapList<Record<string, unknown>>(data);
+    },
+    enabled: !!hostname,
+    staleTime: 30_000,
+  });
+}
+
+export function useHealthProbes(hostname: string) {
+  return useQuery({
+    queryKey: queryKeys.hostMonitor.probes(hostname),
+    queryFn: async () => {
+      if (!hostname) return [];
+      const data = await agentApi.getHealthProbes({ hostname });
+      return unwrapList<Record<string, unknown>>(data);
+    },
+    enabled: !!hostname,
+  });
+}
+
+export function usePortPolicy(hostname: string) {
+  return useQuery({
+    queryKey: queryKeys.hostMonitor.portPolicy(hostname),
+    queryFn: async () => {
+      if (!hostname) return { port_filter_mode: 'whitelist', port_whitelist: [] as number[] };
+      const data = await agentApi.getPortPolicy(hostname) as { data?: { port_filter_mode?: string; port_whitelist?: number[] } };
+      return {
+        port_filter_mode: data?.data?.port_filter_mode || 'blacklist',
+        port_whitelist: data?.data?.port_whitelist || [],
+      };
+    },
+    enabled: !!hostname,
+  });
+}

frontend/src/hooks/api/useTerminalSessions.ts

@@ -0,0 +1,70 @@
+// 终端会话列表 — TanStack Query // Logan.Li
+
+import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query';
+import { terminalSessionApi } from '@/services/api';
+import { queryKeys } from './queryKeys';
+
+export interface TerminalSession {
+  id: number;
+  user_id?: number;
+  username: string;
+  server_id: number;
+  server_name: string;
+  server_ip: string;
+  server_port: number;
+  client_ip: string;
+  status: string;
+  duration: number;
+  record_size: number;
+  start_time: string;
+  end_time?: string | null;
+}
+
+type ListParams = {
+  page?: number;
+  page_size?: number;
+  server_id?: number;
+  username?: string;
+  status?: string;
+};
+
+function unwrapList<T>(data: unknown): T[] {
+  if (Array.isArray(data)) return data;
+  if (data && typeof data === 'object' && 'list' in data) {
+    return (data as { list: T[] }).list ?? [];
+  }
+  return [];
+}
+
+export function useTerminalSessions(params: ListParams = { page: 1, page_size: 100 }) {
+  return useQuery({
+    queryKey: queryKeys.terminalSessions(params),
+    queryFn: async () => {
+      const resp = await terminalSessionApi.list(params);
+      return unwrapList<TerminalSession>(resp);
+    },
+  });
+}
+
+export function useTerminalSessionMutations() {
+  const qc = useQueryClient();
+
+  const invalidate = () => qc.invalidateQueries({ queryKey: ['terminal-sessions'] });
+
+  const killMutation = useMutation({
+    mutationFn: (id: number) => terminalSessionApi.kill(id),
+    onSuccess: invalidate,
+  });
+
+  const deleteMutation = useMutation({
+    mutationFn: (id: number) => terminalSessionApi.delete(id),
+    onSuccess: invalidate,
+  });
+
+  const batchDeleteMutation = useMutation({
+    mutationFn: (ids: number[]) => terminalSessionApi.batchDelete(ids),
+    onSuccess: invalidate,
+  });
+
+  return { killMutation, deleteMutation, batchDeleteMutation, invalidate };
+}