合并查询节点：裁判摘录的标题写明是合并查询的结果，不再写成「数据源 合并查询」

backend/app/engine/judge.py

@@ -350,7 +350,8 @@ def _query_excerpt(alias: str, entry: dict[str, Any], rows: set[int], cols: Iter
     total = len(snapshot["rows"])
     # 旧形状的台账条目没记数据源：按快照自己记的找遮罩（证据面板同一个口径）
     source = entry.get("source") or snapshot.get("source")
-    head = f"【{alias}】查询结果（{entry.get('tool') or '查询'} · 数据源 {source or '—'} · 共 {total} 行）"
+    head = (f"【{alias}】合并查询结果（共 {total} 行）" if snapshot.get("source") == MERGE_SOURCE
+            else f"【{alias}】查询结果（{entry.get('tool') or '查询'} · 数据源 {source or '—'} · 共 {total} 行）")
     sql = _clean(str(snapshot.get("sql") or ""))
     lines = [head, f"SQL：{sql[:SQL_CHARS]}{'…' if len(sql) > SQL_CHARS else ''}"]
     if snapshot.get("source") == MERGE_SOURCE:

backend/tests/test_merge_node.py

@@ -432,6 +432,7 @@ def test_judge_excerpt_names_the_inputs_and_masks_their_sources():
     entry = {"kind": "query", "artifact": "m" * 64, "source": MERGE_SOURCE}
     text = judge._query_excerpt("Q3", entry, {0}, ["订单数"], False, lambda _a: snap,
                                 {"merge_members": ["手机号"]})
+    assert text.startswith("【Q3】合并查询结果（共 1 行）")
     assert "合并的输入：s（节点 q_sales，数据源 merge_stores，1 行）、v（节点 q_visits，数据源 merge_members，1 行）" in text
     assert "13800000000" not in text and "遮罩" in text