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/arrow-up-down-Cn71rsC9.js

@@ -0,0 +1 @@
+import{i as o}from"./index-Dmami9WE.js";const e=[["path",{d:"m21 16-4 4-4-4",key:"f6ql7i"}],["path",{d:"M17 20V4",key:"1ejh1v"}],["path",{d:"m3 8 4-4 4 4",key:"11wl7u"}],["path",{d:"M7 4v16",key:"1glfcx"}]],a=o("arrow-up-down",e);export{a as A};