feat(data-annotation): 添加表格序号列并移除任务ID列

- 添加序号列显示当前页码计算后的行号
- 移除原有的任务ID列
- 序号列居中对齐宽度为80px
- 序号基于当前页码和页面大小动态计算
- 保持表格

frontend/src/pages/DataAnnotation/Home/DataAnnotation.tsx

@@ -155,17 +155,23 @@ export default function DataAnnotation() {
   ];
 
   const columns: ColumnType<AnnotationTaskListItem>[] = [
+    {
+      title: "序号",
+      key: "index",
+      width: 80,
+      align: "center" as const,
+      render: (_value: unknown, _record: AnnotationTaskListItem, index: number) => {
+        const current = pagination.current ?? 1;
+        const pageSize = pagination.pageSize ?? tableData.length ?? 0;
+        return (current - 1) * pageSize + index + 1;
+      },
+    },
     {
       title: "任务名称",
       dataIndex: "name",
       key: "name",
       fixed: "left" as const,
     },
-    {
-      title: "任务ID",
-      dataIndex: "id",
-      key: "id",
-    },
     {
       title: "数据集",
       dataIndex: "datasetName",