feat(annotation): implement file version management for annotation feature

Add support for detecting new file versions and switching to them:

Backend Changes:
- Add file_version column to AnnotationResult model
- Create Alembic migration for database schema update
- Implement check_file_version() method to compare annotation and file versions
- Implement use_new_version() method to clear annotations and update version
- Update upsert_annotation() to record file version when saving
- Add new API endpoints: GET /version and POST /use-new-version
- Add FileVersionCheckResponse and UseNewVersionResponse schemas

Frontend Changes:
- Add checkFileVersionUsingGet and useNewVersionUsingPost API calls
- Add version warning banner showing current vs latest file version
- Add 'Use New Version' button with confirmation dialog
- Clear version info state when switching files to avoid stale warnings

Bug Fixes:
- Fix previousFileVersion returning updated value (save before update)
- Handle null file_version for historical data compatibility
- Fix segmented annotation clearing (preserve structure, clear results)
- Fix files without annotations incorrectly showing new version warnings
- Preserve total_segments when clearing segmented annotations

Files Modified:
- frontend/src/pages/DataAnnotation/Annotate/LabelStudioTextEditor.tsx
- frontend/src/pages/DataAnnotation/annotation.api.ts
- runtime/datamate-python/app/db/models/annotation_management.py
- runtime/datamate-python/app/module/annotation/interface/editor.py
- runtime/datamate-python/app/module/annotation/schema/editor.py
- runtime/datamate-python/app/module/annotation/service/editor.py

New Files:
- runtime/datamate-python/alembic.ini
- runtime/datamate-python/alembic/env.py
- runtime/datamate-python/alembic/script.py.mako
- runtime/datamate-python/alembic/versions/20250205_0001_add_file_version.py

frontend/src/pages/DataAnnotation/Annotate/LabelStudioTextEditor.tsx

@@ -8,6 +8,9 @@ import {
   getEditorTaskUsingGet,
   listEditorTasksUsingGet,
   upsertEditorAnnotationUsingPut,
+  checkFileVersionUsingGet,
+  useNewVersionUsingPost,
+  type FileVersionCheckResponse,
 } from "../annotation.api";
 import { AnnotationResultStatus } from "../annotation.model";
 
@@ -269,6 +272,11 @@ export default function LabelStudioTextEditor() {
     return Array.from({ length: segmentTotal }, (_, index) => index);
   }, [segmentTotal]);
 
+  // 文件版本相关状态
+  const [fileVersionInfo, setFileVersionInfo] = useState<FileVersionCheckResponse | null>(null);
+  const [checkingFileVersion, setCheckingFileVersion] = useState(false);
+  const [usingNewVersion, setUsingNewVersion] = useState(false);
+
   const focusIframe = useCallback(() => {
     const iframe = iframeRef.current;
     if (!iframe) return;
@@ -548,6 +556,77 @@ export default function LabelStudioTextEditor() {
     }
   }, [iframeReady, message, postToIframe, project, projectId]);
 
+  const checkFileVersion = useCallback(async (fileId: string) => {
+    if (!projectId || !fileId) return;
+    setCheckingFileVersion(true);
+    try {
+      const resp = (await checkFileVersionUsingGet(projectId, fileId)) as ApiResponse<FileVersionCheckResponse>;
+      const data = resp?.data;
+      if (data) {
+        setFileVersionInfo(data);
+        if (data.hasNewVersion) {
+          modal.warning({
+            title: "文件有新版本",
+            content: (
+              <div className="flex flex-col gap-2">
+                <Typography.Text>
+                  文件已更新到新版本（当前版本: {data.currentFileVersion}，标注版本: {data.annotationFileVersion}）。
+                </Typography.Text>
+                <Typography.Text type="secondary">
+                  点击"使用新版本"可清空当前标注并使用最新版本的文件内容。
+                </Typography.Text>
+              </div>
+            ),
+            okText: "我知道了",
+          });
+        }
+      }
+    } catch (e) {
+      console.error("检查文件版本失败", e);
+    } finally {
+      setCheckingFileVersion(false);
+    }
+  }, [modal, message, projectId]);
+
+  const handleUseNewVersion = useCallback(async () => {
+    if (!selectedFileId) return;
+
+    modal.confirm({
+      title: "确认使用新版本",
+      content: (
+        <div className="flex flex-col gap-2">
+          <Typography.Text>
+            确认使用新版本？这将清空当前标注并使用最新版本的文件内容。
+          </Typography.Text>
+          {fileVersionInfo && (
+            <Typography.Text type="secondary">
+              当前标注版本: {fileVersionInfo.annotationFileVersion}，最新文件版本: {fileVersionInfo.currentFileVersion}
+            </Typography.Text>
+          )}
+        </div>
+      ),
+      okText: "确认",
+      okType: "danger",
+      cancelText: "取消",
+      onOk: async () => {
+        if (!projectId || !selectedFileId) return;
+        setUsingNewVersion(true);
+        try {
+          await useNewVersionUsingPost(projectId, selectedFileId);
+          message.success("已使用新版本并清空标注");
+          setFileVersionInfo(null);
+          await loadTasks({ mode: "reset" });
+          await initEditorForFile(selectedFileId);
+        } catch (e) {
+          console.error("使用新版本失败", e);
+          message.error("使用新版本失败");
+        } finally {
+          setUsingNewVersion(false);
+        }
+      },
+    });
+  }, [modal, message, projectId, selectedFileId, fileVersionInfo, loadTasks, initEditorForFile]);
+
   const advanceAfterSave = useCallback(async (fileId: string, segmentIndex?: number) => {
     if (!fileId) return;
     if (segmented && segmentTotal > 0) {
@@ -815,6 +894,13 @@ export default function LabelStudioTextEditor() {
     return () => window.removeEventListener("message", handler);
   }, [message, origin, saveFromExport]);
 
+  useEffect(() => {
+    if (selectedFileId && project?.supported) {
+      setFileVersionInfo(null);
+      checkFileVersion(selectedFileId);
+    }
+  }, [selectedFileId, project?.supported, checkFileVersion]);
+
   const canLoadMore = taskTotalPages > 0 && taskPage + 1 < taskTotalPages;
   const saveDisabled =
     !iframeReady || !selectedFileId || saving || loadingTaskDetail;
@@ -896,6 +982,22 @@ export default function LabelStudioTextEditor() {
           </Typography.Title>
         </div>
         <div className="flex items-center justify-center">
+          {fileVersionInfo?.hasNewVersion && (
+            <div className="flex items-center gap-2 mr-4">
+              <Typography.Text type="warning" className="text-xs">
+                ⚠ 文件有新版本（{fileVersionInfo.currentFileVersion} > {fileVersionInfo.annotationFileVersion}）
+              </Typography.Text>
+              <Button
+                size="small"
+                type="primary"
+                danger
+                loading={usingNewVersion}
+                onClick={handleUseNewVersion}
+              >
+                使用新版本
+              </Button>
+            </div>
+          )}
           <Button
             type="primary"
             icon={<SaveOutlined />}