feat: workspace 目录树服务端懒加载

- api.ts: listWorkspaceDirectories 支持 parent_path 查询; WorkspaceDirectory 增加 has_children; 同步 WorkspaceBoundApi 签名
- AuthContext: 绑定透传 parentPath
- scriptWorkspaceStore: 新增 expandedPaths/loadingChildrenPaths/loadedChildPaths, loadChildren/toggleExpanded, 局部刷新 createFolder/deleteDirectory
- WorkspaceTree: 移除 useState, 改为受控展开/加载状态
- ScriptExplorer: 从 store 读取并透传展开状态与 toggle

frontend/app/components/platform/ScriptExplorer.tsx

@@ -1,6 +1,7 @@
 import { type ChangeEvent, type MouseEvent as ReactMouseEvent, type RefObject, useMemo } from "react";
 import Icon from "../common/Icon";
 import { WorkspaceTreeGroup } from "~/features/platform/WorkspaceTree";
+import { useScriptWorkspaceStore } from "~/features/platform/state/scriptWorkspaceStore";
 import type { ScriptItem, WorkspaceDirectory } from "~/services/api";
 import { type AuthUser } from "~/context/AuthContext";
 
@@ -50,6 +51,12 @@ export function ScriptExplorer({
   uploadInputRef,
   onHandleUpload,
 }: ScriptExplorerProps) {
+  const expandedPaths = useScriptWorkspaceStore((s) => s.expandedPaths);
+  const loadingChildrenPaths = useScriptWorkspaceStore(
+    (s) => s.loadingChildrenPaths,
+  );
+  const onToggle = useScriptWorkspaceStore((s) => s.toggleExpanded);
+
   const memberScriptGroups = useMemo(() => {
     const visibleScripts =
       user?.is_system_admin === true
@@ -185,6 +192,9 @@ export function ScriptExplorer({
                     : undefined
                 }
                 readOnly={group.user?.user_id !== user?.user_id}
+                expandedPaths={expandedPaths}
+                onToggle={onToggle}
+                loadingChildrenPaths={loadingChildrenPaths}
               />
             ))}
             {filteredScripts.length === 0 && (