curl -X POST http://127.0.0.1:20401/survey/preregister \
-H "Content-Type: application/json" \
-d '{"project_no":"OE-2026-09","row_count":21,"fields":["dept","grade_band","tenure_band","region"],"distribution":"dept x tenure_band"}'
预期回执(预登记号):
{"ok": true, "prereg_no": "PR-202609-0287", "row_count": 21}
PR-202609-0287 生成
(当期批次内有效;样本导入前须先完成预登记)。