feat: add bounded KIS account read recovery

trex_core/application/intents.py

@@ -115,6 +115,7 @@ class IntentService:
         default_order_timeout_sec: Optional[int] = None,
         warn_store=None,  # Optional[ReconcileWarningStore] — BAT-050 / REQ-104
         entry_allowed_fn: Optional[Callable[[], bool]] = None,
+        buy_guard_fn: Optional[Callable[[BuyIntent], Optional[str]]] = None,
     ) -> None:
         self._svc = slot_service
         self._repo = slot_repo
@@ -138,6 +139,10 @@ class IntentService:
         # When returns False, BuyIntent is rejected with reason 'day_start_load_failed'.
         # SellIntent is NOT gated by this (REQ-114 AC-5: 청산 경로 영향 없음).
         self._entry_allowed_fn: Optional[Callable[[], bool]] = entry_allowed_fn
+        # dcy-041 / GitHub #45: opt-in bounded cash-capacity admission guard.
+        # The callable returns a stable rejection reason or None. SellIntent is
+        # deliberately outside this gate.
+        self._buy_guard_fn = buy_guard_fn
 
     # ------------------------------------------------------------
     def lookup(self, intent_id: str) -> Optional[IntentDecision]:
@@ -270,6 +275,15 @@ 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:
+                try:
+                    guard_reason = 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