HEL-270: 修复闭期补录未提交即回滚丢失（补回归测试）

Co-authored-by: multica-agent <github@multica.ai>

tests/test_period_close.py

@@ -110,6 +110,33 @@ class PeriodCloseTests(LedgerBase):
         again = period_close.close_payload(self.connection, self.MONTH)
         self.assertEqual(digest, again["snapshot_hash"])
 
+    def test_late_arrivals_survive_connection_close(self) -> None:
+        """Regression: the reconcile handler closes its connection right after
+        recording locked rows; uncommitted inserts used to vanish silently."""
+        from bank_importer.db import connect as db_connect
+
+        self._cover_month()
+        self._close()
+        late_id = self.add_row(
+            self.company_a, own_account="6222000000000001",
+            expense="12.00", at="2026-07-28T11:00:00",
+        )
+        writable, locked = period_close.split_writable_row_ids(self.connection, [late_id])
+        self.assertEqual(1, period_close.record_late_arrivals(self.connection, locked, self.admin))
+        self.connection.close()
+        fresh = db_connect(self.db_path)
+        try:
+            rows = fresh.execute(
+                "SELECT source_row_id FROM period_late_arrivals"
+            ).fetchall()
+            audits = fresh.execute(
+                "SELECT action FROM period_audit_events WHERE action = 'late_arrival'"
+            ).fetchall()
+        finally:
+            fresh.close()
+        self.assertEqual([late_id], [r["source_row_id"] for r in rows])
+        self.assertEqual(1, len(audits))
+
     def test_snapshot_row_cannot_be_updated(self) -> None:
         self._cover_month()
         self._close()