fix: close broker uncertainty audit gaps

trex_core/application/intents.py

@@ -30,6 +30,7 @@ from uuid import UUID
 
 from trex_core.application.ports import IntentStore
 from trex_core.domain.slot import (
+    SlotAdmissionRejectedError,
     SlotRepository,
     SlotService,
     SlotState,
@@ -275,20 +276,24 @@ class IntentService:
             symbol = _resolve(slot)
             if not symbol:
                 return IntentDecision(intent.intent_id, "rejected", None, "unknown_portfolio")
-            if self._buy_guard_fn is not None:
+            def _admission_precondition(_locked_slot) -> Optional[str]:
+                # Runs inside SlotService's instance-scoped advisory lock. This
+                # makes capacity and cached-cash reservation checks atomic with
+                # the PENDING_BUY transition across same-instance daemons.
+                if (
+                    not is_increase
+                    and self._max_active_slots is not None
+                    and self._repo.count_active(self._instance_key)
+                    >= self._max_active_slots
+                ):
+                    return "capacity_full"
+                if self._buy_guard_fn is None:
+                    return None
                 try:
-                    guard_reason = self._buy_guard_fn(intent)
+                    return self._buy_guard_fn(intent)
                 except Exception:  # noqa: BLE001 - buy guard fails closed
-                    guard_reason = "account_snapshot_unavailable"
-                if guard_reason is not None:
-                    return IntentDecision(
-                        intent.intent_id, "rejected", None, guard_reason
-                    )
-            # M cap applies only to NEW activations (initial buy). An increase on
-            # an already-active asset does not change the active asset count.
-            if (not is_increase and self._max_active_slots is not None
-                    and self._repo.count_active(self._instance_key) >= self._max_active_slots):
-                return IntentDecision(intent.intent_id, "rejected", None, "capacity_full")
+                    return "account_snapshot_unavailable"
+
             # dcy-022 / REQ-068: resolve effective timeout (per-intent > config default).
             effective_timeout = (
                 intent.timeout_sec
@@ -317,6 +322,11 @@ class IntentService:
                     slippage_pct=intent.slippage_pct,
                     venue=intent.venue,
                     extra={"intent_id": intent.intent_id, "symbol": symbol},
+                    precondition=_admission_precondition,
+                )
+            except SlotAdmissionRejectedError as exc:
+                return IntentDecision(
+                    intent.intent_id, "rejected", None, exc.reason
                 )
             except SlotStateMismatchError:
                 continue  # slot changed under us; re-fetch and re-evaluate