fix: guard unmanaged resolution on authoritative balances

Co-authored-by: genichin <4282227+genichin@users.noreply.github.com>

trex_core/application/reconciliation.py

@@ -364,6 +364,18 @@ def _notify_unmanaged_position_transition(
     )
 
 
+def _broker_balances_are_authoritative_for_unmanaged_resolution(broker: BrokerPort) -> bool:
+    marker = getattr(broker, "exposes_full_balance_snapshot", None)
+    if callable(marker):
+        try:
+            return bool(marker())
+        except Exception:  # noqa: BLE001 - fail closed on broker self-report failure
+            return False
+    if isinstance(marker, bool):
+        return marker
+    return True
+
+
 def reconcile_core_holdings(
     *,
     slot_repo,
@@ -535,7 +547,10 @@ def reconcile_core_holdings(
                                     symbol=sym,
                                     quantity=bq,
                                 )
-    if unmanaged_position_store is not None:
+    if (
+        unmanaged_position_store is not None
+        and _broker_balances_are_authoritative_for_unmanaged_resolution(broker)
+    ):
         try:
             for state in unmanaged_position_store.resolve_absent(
                 instance_key=instance_key,
@@ -555,6 +570,11 @@ def reconcile_core_holdings(
                     )
         except Exception:  # noqa: BLE001
             _log.exception("reconcile_core_holdings: unmanaged_position resolve failed")
+    elif unmanaged_position_store is not None:
+        _log.debug(
+            "reconcile_core_holdings: unmanaged_position resolve skipped "
+            "(non-authoritative broker balance view)"
+        )
     # req-0007 / ac-0024: retry pending_resolved for B-case identities no longer mismatched.
     if alarm_emitter is not None and notification_store is not None:
         try: