fix: add close/context-manager to diagnosis store; tighten import boundary

tests/unit/test_baseline_diagnosis_store.py

@@ -4,7 +4,12 @@
 load 往返还原，以及 INFRA 行的可空字段处理。
 """
 
-from adapters.baseline_diagnosis_store import DiagnosisSignalRow, SqliteDiagnosisSignalStore
+import sqlite3
+
+import pytest
+
+from adapters.baseline_diagnosis_store import SqliteDiagnosisSignalStore
+from core.evolution.types import DiagnosisSignalRow
 
 
 def _store(tmp_path):
@@ -78,3 +83,16 @@ def test_null_fields_for_infra_row(tmp_path):
     )
     rows = s.load("r", "fp")
     assert rows[0].error_type is None and rows[0].evolution_target is None and rows[0].infra is True
+
+
+def test_context_manager_closes_connection(tmp_path):
+    # with 块退出后连接关闭，再操作应报 ProgrammingError
+    with SqliteDiagnosisSignalStore(str(tmp_path / "h.db")) as s:
+        s.upsert(
+            DiagnosisSignalRow(
+                "q4", "v4", "r", "fp", "Counting", None, None, "T0", None, False, True, None
+            )
+        )
+        assert s.done_question_ids("r", "fp") == {"q4"}
+    with pytest.raises(sqlite3.ProgrammingError):
+        s.done_question_ids("r", "fp")