fix chat session traces and document paths

src/main/java/com/superbiz/agent/service/DocumentManagementService.java

@@ -260,7 +260,8 @@ public class DocumentManagementService {
     private String saveToLocal(MultipartFile file, String fileName, String category) {
         try {
             // 1. 构建目标路径
-            Path categoryDir = Paths.get(knowledgeBasePath, category);
+            Path baseDir = Paths.get(knowledgeBasePath).normalize();
+            Path categoryDir = baseDir.resolve(category).normalize();
             Files.createDirectories(categoryDir);
 
             Path targetPath = categoryDir.resolve(fileName);
@@ -268,8 +269,9 @@ public class DocumentManagementService {
             // 2. 保存文件
             file.transferTo(targetPath.toFile());
 
-            log.info("文件已保存到本地: {}", targetPath);
-            return targetPath.toString();
+            String relativePath = baseDir.relativize(targetPath.normalize()).toString().replace("\\", "/");
+            log.info("文件已保存到本地: {}, storedPath={}", targetPath, relativePath);
+            return relativePath;
 
         } catch (IOException e) {
             throw new DocumentProcessException(
@@ -287,7 +289,7 @@ public class DocumentManagementService {
     private void cleanupLocalFile(String localPath) {
         if (localPath != null) {
             try {
-                Files.deleteIfExists(Paths.get(localPath));
+                Files.deleteIfExists(resolveLocalPath(localPath));
                 log.info("已清理本地文件: {}", localPath);
             } catch (IOException e) {
                 log.warn("清理本地文件失败: {}", localPath, e);
@@ -357,7 +359,7 @@ public class DocumentManagementService {
         // 删除本地文件
         if (doc.getFilePath() != null) {
             try {
-                Files.deleteIfExists(Paths.get(doc.getFilePath()));
+                Files.deleteIfExists(resolveLocalPath(doc.getFilePath()));
                 log.info("本地文件已删除: {}", doc.getFilePath());
             } catch (IOException e) {
                 log.warn("删除本地文件失败: {}", doc.getFilePath(), e);
@@ -407,6 +409,26 @@ public class DocumentManagementService {
         return null;
     }
 
+    private Path resolveLocalPath(String filePath) {
+        Path path = Paths.get(filePath).normalize();
+        if (path.isAbsolute()) {
+            return path;
+        }
+
+        Path basePath = Paths.get(knowledgeBasePath).toAbsolutePath().normalize();
+        Path baseName = basePath.getFileName();
+        if (baseName != null && path.startsWith(baseName) && basePath.getParent() != null) {
+            return basePath.getParent().resolve(path).normalize();
+        }
+
+        Path pathFromWorkingDir = path.toAbsolutePath().normalize();
+        if (pathFromWorkingDir.startsWith(basePath)) {
+            return pathFromWorkingDir;
+        }
+
+        return basePath.resolve(path).normalize();
+    }
+
     /**
      * 转换为响应 DTO
      */