feat(bat-053): 그날-시작 KIS 인증정보 fetch + fail-safe 로드 (REQ-112~115)

REQ-112: BrokerCredentialPayload/TradingContext 데이터클래스 + PortfolioHubReadPort.fetch_broker_credential() 포트 메서드 + hub_read 어댑터(_fetch_user_info 헬퍼 추출) + stub_read 결정론 stub
REQ-113: DaemonInstanceConfig/DaemonConfig.credential_fetch_enabled opt-in(기본 False) + TOML 파싱 + break-glass(TREX_KIS_BROKER_BREAK_GLASS) 감지
REQ-114: SnapshotScheduler._maybe_fetch_credential() — fail-closed 3조건(unavailable/broker-null/trading_disabled) + CRITICAL 알람 DAY_START_LOAD_FAILED + IntentService entry_allowed_fn 게이트(BuyIntent 차단, SellIntent 통과)
REQ-115: 그날 고정 캐시(_cached_credential/_credential_date) — 동일 날짜 재fetch 방지 + app_secret 메모리 한정(Redis 미기록)

스텁 기반 구현: 실 portfolio-hub/네트워크 없이 AC 전부 단위 테스트.
회귀: credential_fetch_enabled=False(기본) 경로 byte-for-byte 보존.
745 passed, 47 skipped (0 failed).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VHtM5Ws1HKCKQ4JGi6GRb5

trex_core/application/intents.py

@@ -25,7 +25,7 @@ from __future__ import annotations
 from dataclasses import dataclass, field
 from datetime import datetime
 from decimal import Decimal
-from typing import Any, Optional
+from typing import Any, Callable, Optional
 from uuid import UUID
 
 from trex_core.application.ports import IntentStore
@@ -110,6 +110,7 @@ class IntentService:
         max_active_slots: Optional[int] = None,
         default_order_timeout_sec: Optional[int] = None,
         warn_store=None,  # Optional[ReconcileWarningStore] — BAT-050 / REQ-104
+        entry_allowed_fn: Optional[Callable[[], bool]] = None,
     ) -> None:
         self._svc = slot_service
         self._repo = slot_repo
@@ -128,6 +129,11 @@ class IntentService:
         # BAT-050 / REQ-104: reconcile-warning gate store (Optional).
         # When None, gate is skipped (backward compat, NFR-4).
         self._warn_store = warn_store
+        # dcy-036 / REQ-114: day-start entry gate (Optional callable → bool).
+        # When None or returns True, gate passes (backward compat / opt-in=False).
+        # 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
 
     # ------------------------------------------------------------
     def lookup(self, intent_id: str) -> Optional[IntentDecision]:
@@ -196,7 +202,22 @@ class IntentService:
           position; M cap does NOT apply (active asset count unchanged).
         - PENDING_* slot -> in-flight conflict (already_active).
         Single intent thread + instance-scoped advisory lock serialize
-        admissions (dcy-020 OQ-1)."""
+        admissions (dcy-020 OQ-1).
+
+        dcy-036 / REQ-114: entry gate — if entry_allowed_fn returns False,
+        BuyIntent is rejected before any slot lookup."""
+
+        # dcy-036 / REQ-114: day-start entry gate (fail-closed).
+        # None or True → pass; False → reject new entry.
+        # SellIntent is NOT checked (청산 경로는 차단하지 않음 AC-5).
+        if self._entry_allowed_fn is not None:
+            try:
+                if not self._entry_allowed_fn():
+                    return IntentDecision(
+                        intent.intent_id, "rejected", None, "day_start_load_failed"
+                    )
+            except Exception:  # noqa: BLE001 - gate failure → fail-open (conservative)
+                pass
 
         def _resolve(sl):
             pid = sl.portfolio_id