feat(rag): 添加文件相对路径支持功能

- 在FileInfo DTO中新增relativePath字段
- 实现文件相对路径的规范化处理逻辑
- 将文件相对路径存储到元数据中
- 前端添加文件路径解析和显示功能
- 优化路径分隔符统一处理机制
- 更新文件列表展示逻辑以支持路径层级结构

frontend/src/pages/KnowledgeBase/components/AddDataDialog.tsx

@@ -26,19 +26,20 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
 
   const [selectedFilesMap, setSelectedFilesMap] = useState({});
 
+  const PATH_SEPARATOR = "/";
   const normalizePath = (value?: string) =>
-    (value ?? "").replace(/\\/g, "/");
+    (value ?? "").replace(/\\/g, PATH_SEPARATOR);
 
-  const resolveRelativeFileName = (file: DatasetFile) => {
+  const resolveRelativePath = (file: DatasetFile) => {
     const normalizedName = normalizePath(file.fileName);
-    if (normalizedName.includes("/")) {
+    if (normalizedName.includes(PATH_SEPARATOR)) {
       return normalizedName.replace(/^\/+/, "");
     }
 
     const rawPath = normalizePath(file.path || file.filePath);
     const datasetId = String(file.datasetId || "");
     if (rawPath && datasetId) {
-      const marker = `/${datasetId}/`;
+      const marker = `${PATH_SEPARATOR}${datasetId}${PATH_SEPARATOR}`;
       const index = rawPath.lastIndexOf(marker);
       if (index >= 0) {
         const relative = rawPath
@@ -50,7 +51,7 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
       }
     }
 
-    const fallbackName = rawPath.split("/").pop();
+    const fallbackName = rawPath.split(PATH_SEPARATOR).pop();
     return fallbackName || file.fileName;
   };
 
@@ -158,7 +159,8 @@ export default function AddDataDialog({ knowledgeBase, onDataAdded }) {
       const requestData = {
         files: Object.values(selectedFilesMap).map((file) => ({
           id: String(file.id),
-          fileName: resolveRelativeFileName(file as DatasetFile),
+          fileName: (file as DatasetFile).fileName,
+          relativePath: resolveRelativePath(file as DatasetFile),
         })),
         processType: newKB.processType,
         chunkSize: Number(newKB.chunkSize), // 确保是数字类型