feat(kevin): reconcile Alpaca bracket auto-closes + order status

Bracket stop-loss/take-profit legs fill at Alpaca without passing through the executor, so those closes (and their P&L) were invisible locally.

- broker: add get_order(nested) + list_orders to BaseBroker/AlpacaBroker (+ SimulatedBroker); BrokerOrder carries child legs

- Trade gains broker_order_id (migration f6a7b8c9d0e1); executor stamps the entry order id

- new api_gateway trade-reconcile loop: books a closing SELL + realized P&L when a bracket leg fills (idempotent on the leg order id), syncs PENDING->terminal status, logs drift; runs alongside portfolio_sync

[ci skip]

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/services/test_trade_executor.py

@@ -912,6 +912,34 @@ class TestExecutorDBPersistence:
         assert trade_obj.ticker == "AAPL"
         assert trade_obj.signal_id == signal.signal_id
 
+    @pytest.mark.asyncio
+    async def test_entry_trade_records_broker_order_id(self):
+        """The persisted entry Trade must carry the Alpaca order id so
+        reconciliation can find the bracket order later."""
+        config = _make_config()
+        broker = _mock_broker(positions=[], account=_make_account(100_000))
+        publisher = AsyncMock()
+        publisher.publish = AsyncMock(return_value=b"1-0")
+        counters = {
+            "trades_executed": MagicMock(),
+            "rejections": MagicMock(),
+            "fill_latency": MagicMock(),
+        }
+
+        signal = _make_kevin_signal(direction=SignalDirection.LONG)
+        mock_session = AsyncMock()
+        mock_session.add = MagicMock()
+        mock_session.commit = AsyncMock()
+        db_factory = _make_mock_db_session_factory(mock_session)
+
+        with patch.object(RiskManager, "check_risk", return_value=(True, "approved")):
+            await process_signal(
+                signal, RiskManager(config, broker), broker, publisher, counters, db_factory
+            )
+
+        trade_obj = mock_session.add.call_args[0][0]
+        assert trade_obj.broker_order_id == "ord-123"
+
     @pytest.mark.asyncio
     async def test_trade_not_persisted_without_db(self):
         """When db_session_factory is None, no DB write should happen."""