fix: preserve SOR execution venue separately

tests/application/test_venue_intent_flow.py

@@ -33,7 +33,7 @@ class RecordingBroker:
         return OrderAck(
             accepted=True,
             broker_order_id=f"order-{len(self.orders)}",
-            venue=self.actual_venue or req.venue,
+            venue=req.venue,
         )
 
     def poll_fill(self, broker_order_id: str, *, side: str, symbol: str) -> FillStatus:
@@ -121,7 +121,7 @@ def test_invalid_venue_is_rejected_before_slot_transition(invalid_venue: str) ->
     assert repo.list_slots("default")[0].status is SlotState.INACTIVE
 
 
-def test_omitted_wire_venue_is_sor_then_actual_venue_is_persisted() -> None:
+def test_omitted_wire_venue_remains_sor_for_cancel_and_restart() -> None:
     repo = InMemorySlotRepository()
     service = SlotService(repo)
     intents = IntentService(
@@ -153,7 +153,9 @@ def test_omitted_wire_venue_is_sor_then_actual_venue_is_persisted() -> None:
     execution.run_once()
     dispatched = repo.fetch_slot(slot_id)
     assert broker.orders[0].venue == "SOR"
-    assert dispatched is not None and dispatched.venue == "NXT"
+    # Ack cannot turn SOR routing provenance into an execution venue. Actual
+    # KRX/NXT is established by fill polling and stored on the ledger trade.
+    assert dispatched is not None and dispatched.venue == "SOR"
 
 
 def test_inactive_transition_resets_venue_to_krx() -> None: