fix: persist uncertain cancel outcomes

tests/application/test_execution_cancel.py

@@ -13,7 +13,13 @@ from datetime import datetime, timedelta, timezone
 
 from trex_core.adapters.ledger.in_memory import InMemoryLedger
 from trex_core.adapters.persistence.in_memory_intent_store import InMemoryIntentStore
-from trex_core.application.broker_port import BalanceItem, FillStatus, OrderAck
+from trex_core.application.broker_port import (
+    BalanceItem,
+    CancelOutcome,
+    CancelState,
+    FillStatus,
+    OrderAck,
+)
 from trex_core.application.execution import ExecutionService
 from trex_core.application.intents import BuyIntent, IntentService, SellIntent
 from trex_core.application.ledger_outbox import InMemoryLedgerOutbox, LedgerWriter
@@ -46,8 +52,8 @@ class ProgrammableBroker:
         self.polls += 1
         return self.responder(side)
 
-    def cancel_order(self, broker_order_id, *, side, symbol, qty):
-        return True
+    def cancel_order(self, broker_order_id, *, side, symbol, qty, venue="KRX"):
+        return CancelOutcome(CancelState.REQUESTED)
 
     def get_balance(self):
         # M2 (dcy-020/REQ-062): sell dispatch reads the broker balance.