feat(knowledge-management): 添加知识管理搜索功能和统计接口

- 新增知识条目搜索查询和响应DTO
- 实现知识管理统计功能，包括总数、文件数和总大小
- 添加数据库查询方法支持文件搜索和统计计算
- 创建知识条目搜索控制器提供REST API
- 在前端添加知识管理搜索页面和相关组件
- 更新前端路由配置添加搜索页面入口
- 移除RAG索引服务中的重复统计功能
- 优化前端页面统计数据显示和刷新逻辑

frontend/src/routes/routes.ts

@@ -9,6 +9,7 @@ import DatasetCreate from "@/pages/DataManagement/Create/CreateDataset";
 import DatasetDetail from "@/pages/DataManagement/Detail/DatasetDetail";
 import KnowledgeManagementPage from "@/pages/KnowledgeManagement/Home/KnowledgeManagementPage";
 import KnowledgeSetDetail from "@/pages/KnowledgeManagement/Detail/KnowledgeSetDetail";
+import KnowledgeManagementSearch from "@/pages/KnowledgeManagement/Search/KnowledgeManagementSearch";
 
 import DataCleansing from "@/pages/DataCleansing/Home/DataCleansing";
 import CleansingTaskCreate from "@/pages/DataCleansing/Create/CreateTask";
@@ -116,6 +117,10 @@ const router = createBrowserRouter([
             index: true,
             Component: KnowledgeManagementPage,
           },
+          {
+            path: "search",
+            Component: KnowledgeManagementSearch,
+          },
           {
             path: "detail/:id",
             Component: KnowledgeSetDetail,