feat(check): 同一行按单元格；业绩条款不再误跳；重复条目只合并显示（C5 修订）

- 送给模型的「同一行」在有框线的表格里按单元格分行
- 「以合同签订时间为准」不再被当成「签订合同时才交」，要附合同的业绩评分项照常查
- 重复的要求各自判断，问题接口给出 duplicate_ids，查标页同组折叠显示、一起处理
- 决策 C5 修订记入 decisions.md；开发集召回 74%、致命级 25/32

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

server/tests/test_check_flow.py

@@ -360,3 +360,19 @@ async def test_recheck_reuses_unchanged_model_results(user: User) -> None:
     assert n == 0
     results = (await user.get(f"/check-runs/{second['id']}/item-results")).json()["items"]
     assert all(r["bid_citations"] for r in results if r["verdict"] == "responded")  # 沿用的结论证据也找回来了
+
+
+async def test_duplicate_requirements_are_checked_separately_and_grouped_for_display(user: User) -> None:
+    """重复的要求（决策 C5 修订）：各自判断、各出一个问题，问题接口给出同组的其他问题，界面折叠显示。"""
+    project_id, tender_id = await project_with_tender(user)
+    await run_parse(user, tender_id)
+    for _ in range(2):
+        r = await user.post(
+            f"/projects/{project_id}/checklist/items",
+            json={"categories": ["qualification"], "title": "须提供船舶防爆检验报告"},
+        )
+        assert r.status_code == 201, r.text
+    bid = await upload_bid(user, project_id, "bid-mini-v1.pdf")
+    run = await run_check(user, project_id, [bid["id"]])
+    dup = [f for f in await findings(user, run["id"]) if "船舶防爆" in f["title"]]
+    assert len(dup) == 2 and dup[0]["duplicate_ids"] == [dup[1]["id"]] and dup[1]["duplicate_ids"] == [dup[0]["id"]]