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/pages/KnowledgeManagement/Home/KnowledgeManagementPage.tsx

@@ -1,5 +1,5 @@
-import { useEffect, useMemo, useState } from "react";
-import { Card, Button, Table, Tooltip, Tag, App } from "antd";
+import { useCallback, useEffect, useMemo, useState } from "react";
+import { Card, Button, Table, Tooltip, Tag, App, Statistic } from "antd";
 import { DeleteOutlined, EditOutlined } from "@ant-design/icons";
 import { useNavigate } from "react-router";
 import CardView from "@/components/CardView";
@@ -8,6 +8,7 @@ import TagManager from "@/components/business/TagManagement";
 import useFetchData from "@/hooks/useFetchData";
 import {
   deleteKnowledgeSetByIdUsingDelete,
+  getKnowledgeManagementStatisticsUsingGet,
   queryKnowledgeSetsUsingGet,
 } from "../knowledge-management.api";
 import {
@@ -15,7 +16,7 @@ import {
   mapKnowledgeSet,
   KnowledgeSetView,
 } from "../knowledge-management.const";
-import { KnowledgeSet } from "../knowledge-management.model";
+import { KnowledgeManagementStatistics, KnowledgeSet } from "../knowledge-management.model";
 import CreateKnowledgeSet from "../components/CreateKnowledgeSet";
 import {
   createDatasetTagUsingPost,
@@ -23,6 +24,27 @@ import {
   queryDatasetTagsUsingGet,
   updateDatasetTagUsingPut,
 } from "@/pages/DataManagement/dataset.api";
+import { formatBytes } from "@/utils/unit";
+
+type StatisticsItem = {
+  title: string;
+  value: number | string;
+};
+
+const DEFAULT_STATISTICS: StatisticsItem[] = [
+  {
+    title: "知识集总数",
+    value: 0,
+  },
+  {
+    title: "文件总数",
+    value: 0,
+  },
+  {
+    title: "总大小",
+    value: "0 B",
+  },
+];
 
 export default function KnowledgeManagementPage() {
   const navigate = useNavigate();
@@ -31,6 +53,9 @@ export default function KnowledgeManagementPage() {
   const [isEdit, setIsEdit] = useState(false);
   const [currentSet, setCurrentSet] = useState<KnowledgeSet | null>(null);
   const [tags, setTags] = useState<string[]>([]);
+  const [statisticsData, setStatisticsData] = useState<StatisticsItem[]>(
+    DEFAULT_STATISTICS
+  );
 
   useEffect(() => {
     const fetchTags = async () => {
@@ -75,10 +100,45 @@ export default function KnowledgeManagementPage() {
     0
   );
 
+  const fetchStatistics = useCallback(async () => {
+    try {
+      const { data } = await getKnowledgeManagementStatisticsUsingGet();
+      const stats = data as KnowledgeManagementStatistics | undefined;
+      setStatisticsData([
+        {
+          title: "知识集总数",
+          value: stats?.totalKnowledgeSets ?? 0,
+        },
+        {
+          title: "文件总数",
+          value: stats?.totalFiles ?? 0,
+        },
+        {
+          title: "总大小",
+          value: formatBytes(stats?.totalSize ?? 0),
+        },
+      ]);
+    } catch {
+      message.error("统计数据加载失败");
+      setStatisticsData(DEFAULT_STATISTICS);
+    }
+  }, [message]);
+
+  const refreshAll = useCallback(
+    async (extraParams: Record<string, unknown> = {}) => {
+      await Promise.all([fetchData(extraParams), fetchStatistics()]);
+    },
+    [fetchData, fetchStatistics]
+  );
+
+  useEffect(() => {
+    fetchStatistics();
+  }, [fetchStatistics]);
+
   const handleDeleteSet = async (setId: string) => {
     await deleteKnowledgeSetByIdUsingDelete(setId);
     message.success("知识集删除成功");
-    fetchData({ pageOffset: 0 });
+    await refreshAll({ pageOffset: 0 });
   };
 
   const operations = [
@@ -191,6 +251,9 @@ export default function KnowledgeManagementPage() {
       <div className="flex items-center justify-between">
         <h1 className="text-xl font-bold">知识管理</h1>
         <div className="flex gap-2 items-center">
+          <Button onClick={() => navigate("/data/knowledge-management/search")}>
+            全库搜索
+          </Button>
           <TagManager
             onCreate={createDatasetTagUsingPost}
             onDelete={(ids: string) => deleteDatasetTagUsingDelete({ ids })}
@@ -201,7 +264,7 @@ export default function KnowledgeManagementPage() {
             isEdit={isEdit}
             data={currentSet}
             onUpdate={() => {
-              fetchData();
+              refreshAll();
             }}
             onClose={() => {
               setIsEdit(false);
@@ -211,6 +274,20 @@ export default function KnowledgeManagementPage() {
         </div>
       </div>
 
+      <div className="grid grid-cols-1 gap-4">
+        <Card>
+          <div className="grid grid-cols-3">
+            {statisticsData.map((item) => (
+              <Statistic
+                title={item.title}
+                key={item.title}
+                value={`${item.value}`}
+              />
+            ))}
+          </div>
+        </Card>
+      </div>
+
       <SearchControls
         searchTerm={searchParams.keyword}
         onSearchChange={handleKeywordChange}
@@ -221,7 +298,7 @@ export default function KnowledgeManagementPage() {
         viewMode={viewMode}
         onViewModeChange={setViewMode}
         showViewToggle
-        onReload={fetchData}
+        onReload={refreshAll}
       />
 
       {viewMode === "card" ? (