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。

backend/static/assets/download-Vuij9wGr.js

@@ -0,0 +1 @@
+import{i as o}from"./index-Dmami9WE.js";const a=[["path",{d:"M12 15V3",key:"m9g1x1"}],["path",{d:"M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4",key:"ih7n3h"}],["path",{d:"m7 10 5 5 5-5",key:"brsn70"}]],e=o("download",a);export{e as D};