feat: 知识库递归导入（从指定父节点，不需要空间权限）

- feishu_service.py: import_space_nodes 改为 import_nodes_from_parent
  从指定父节点递归获取子节点，不需要空间级别权限
- admin_knowledge.py: import API 增加 parent_node_token 参数
- api.ts/App.vue: 前端增加父节点 NodeToken 输入框

ai_knowledge_base_v2/apps/admin-web/src/services/api.ts

@@ -106,6 +106,11 @@ export const api = {
   updateKnowledge: (id: number, payload: Record<string, unknown>) =>
     request<KnowledgeItem>(`/admin/knowledge/${id}`, { method: "PUT", body: JSON.stringify(payload) }),
   deleteKnowledge: (id: number) => request<null>(`/admin/knowledge/${id}`, { method: "DELETE" }),
+  importKnowledgeFromSpace: (body: Record<string, string>) =>
+    request<{ imported: number; skipped: number; nodes: { name: string; nodeToken: string; status: string; id?: number }[] }>(
+      "/admin/knowledge/import",
+      { method: "POST", body: JSON.stringify(body) },
+    ),
   prompt: () => request<{ promptContent: string }>("/admin/prompt"),
   savePrompt: (promptContent: string) =>
     request<{ promptContent: string }>("/admin/prompt", { method: "PUT", body: JSON.stringify({ promptContent }) }),