feat: isolate strategy-owned KIS balances

trex_core/adapters/broker/kis.py

@@ -138,6 +138,7 @@ class KISBroker:
             "appkey": self._app_key,
             "appsecret": self._app_secret,
             "tr_id": tr_id,
+            "custtype": "P",
             "content-type": "application/json; charset=utf-8",
         }
 
@@ -343,6 +344,49 @@ class KISBroker:
             out.append(BalanceItem(symbol=symbol, hldg_qty=qty))
         return out
 
+    def get_available_cash(self, *, price_check_code: str = "005930") -> int:
+        """Return KIS cash-only buy capacity (`nrcvb_buy_amt`).
+
+        This is intentionally separate from ``BrokerPort``. An account
+        compatibility service may use it to refresh per-strategy portfolio
+        budgets without teaching the domain/Core about mixed manual holdings.
+        """
+        cano, product = self._account()
+        params = {
+            "CANO": cano,
+            "ACNT_PRDT_CD": product,
+            "PDNO": str(price_check_code).zfill(6),
+            # KIS recommends market-order mode when checking cash-only buying
+            # capacity so the symbol's margin ratio is reflected.
+            "ORD_UNPR": "0",
+            "ORD_DVSN": "01",
+            "CMA_EVLU_AMT_ICLD_YN": "Y",
+            "OVRS_ICLD_YN": "N",
+        }
+        try:
+            headers = self._headers("VTTC8908R" if self._mock else "TTTC8908R")
+            response = httpx.get(
+                f"{self._base_url}/uapi/domestic-stock/v1/trading/inquire-psbl-order",
+                headers=headers,
+                params=params,
+                timeout=self._timeout,
+            )
+            response.raise_for_status()
+            payload = response.json()
+        except (httpx.HTTPError, KeyError, TypeError, ValueError):
+            raise BrokerBalanceError("transport_failed") from None
+        if not isinstance(payload, dict):
+            raise BrokerBalanceError("malformed_response")
+        if str(payload.get("rt_cd")) != "0":
+            raise BrokerBalanceError("broker_rejected")
+        output = payload.get("output")
+        if not isinstance(output, dict):
+            raise BrokerBalanceError("malformed_response")
+        amount = _safe_int(output.get("nrcvb_buy_amt"))
+        if amount is None or amount < 0:
+            raise BrokerBalanceError("malformed_response")
+        return amount
+
     def get_current_price(self, symbol: str, market: str = "J") -> Optional[Decimal]:
         """Current traded price `stck_prpr` via KIS inquire-price (REQ-038, REQ-118).