refactor(annotation): 简化文本标注编辑器的段落管理功能

- 移除段落统计相关的数据结构和缓存逻辑
- 删除段落切换确认对话框和自动保存选项
- 简化段落加载和状态管理流程
- 将段落列表视图替换为简单的进度显示
- 更新API接口以支持单段内容获取
- 重构后端服务实现单段内容查询功能

frontend/src/pages/DataAnnotation/annotation.api.ts

@@ -80,8 +80,12 @@ export function getEditorTaskUsingGet(
   return get(`/api/annotation/editor/projects/${projectId}/tasks/${fileId}`, params);
 }
 
-export function getEditorTaskSegmentsUsingGet(projectId: string, fileId: string) {
-  return get(`/api/annotation/editor/projects/${projectId}/tasks/${fileId}/segments`);
+export function getEditorTaskSegmentUsingGet(
+  projectId: string,
+  fileId: string,
+  params: { segmentIndex: number }
+) {
+  return get(`/api/annotation/editor/projects/${projectId}/tasks/${fileId}/segments`, params);
 }
 
 export function upsertEditorAnnotationUsingPut(