fix: persist uncertain cancel outcomes

tests/application/test_execution.py

@@ -7,7 +7,12 @@ from __future__ import annotations
 
 from trex_core.adapters.broker.paper import PaperBroker
 from trex_core.adapters.persistence.in_memory_intent_store import InMemoryIntentStore
-from trex_core.application.broker_port import FillStatus, OrderAck
+from trex_core.application.broker_port import (
+    CancelOutcome,
+    CancelState,
+    FillStatus,
+    OrderAck,
+)
 from trex_core.application.execution import ExecutionService
 from trex_core.application.intents import BuyIntent, IntentService, SellIntent
 from trex_core.domain.slot import SlotService, SlotState
@@ -78,7 +83,10 @@ def test_unknown_submit_outcome_stays_dispatched_without_retry():
 
         def cancel_order(self, broker_order_id, *, side, symbol, qty, venue="KRX"):
             self.cancel_count += 1
-            return False
+            return CancelOutcome(
+                CancelState.UNKNOWN,
+                "submission_outcome_unknown",
+            )
 
     broker = UnknownOutcomeBroker()
     repo, svc, intents, execution = _wire(broker)