feat(intents): dcy-011 buy intent portfolio_id 필수 계약 + ledger skip 가시화 (BAT-015)

dcy-011 전 주기 delivery. issue #6(buy 식별자 정정) + issue #11(ledger silent skip) 흡수.
거버넌스: 기존 Implemented REQ는 change-req, 신규 기능만 신규 REQ(OQ-3).

- REQ-007 (change-req): buy admission portfolio_id 필수화 + SnapshotStore symbol
  resolve + unknown_portfolio 거부 (hard cutover, OQ-1/OQ-2)
- REQ-021 (change-req): buy 메시지 payload symbol 제거
- REQ-018 (change-req): _record_ledger skip 가시화 (WARN + ledger_skipped 카운터)
- REQ-055 (신규): closed↔ledger_outbox anti-join 운영 점검 find_ledger_gap_slots

코드: intents.py(BuyIntent portfolio_id 필수 + resolve_symbol 주입 + _admit_buy
reject 분기), messaging_handlers.py, runtime/daemon.py(_resolve_symbol 배선),
execution.py(skip WARN 로그), adapters/persistence/ops_checks.py(신규 anti-join).

검증: 단위 282 passed/32 skipped, 인프라 게이트(PG+RabbitMQ) 314 passed, ruff clean.
BAT-015(standard) release-candidate. srs/index Next ID → REQ-056.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

trex_core/runtime/daemon.py

@@ -140,7 +140,10 @@ class Daemon:
         self.slot_repo = PostgreSQLSlotRepository(config.dsn)
         self.intent_store = PostgreSQLIntentStore(config.dsn)
         self.slot_service = SlotService(self.slot_repo)
-        self.intent_service = IntentService(self.slot_service, self.slot_repo, self.intent_store)
+        self.intent_service = IntentService(
+            self.slot_service, self.slot_repo, self.intent_store,
+            resolve_symbol=self._resolve_symbol,
+        )
         self.broker = _build_broker(config)
         self.outbox = PostgreSQLLedgerOutbox(config.dsn)
         self.ledger_writer = LedgerWriter(self.outbox, _build_ledger(config))
@@ -185,6 +188,13 @@ class Daemon:
             config=config.safety_sell,
         )
 
+    # ------------------------------------------------------------ buy symbol resolve
+    def _resolve_symbol(self, portfolio_id: str):
+        """dcy-011 / REQ-007: resolve symbol from the universe snapshot for a
+        portfolio_id at buy admission (None → unknown_portfolio reject)."""
+        asset = self.snapshot_store.get(portfolio_id)
+        return asset.symbol if asset is not None else None
+
     # ------------------------------------------------------------ event hook
     def _make_event_emitter(self):
         def emit(event_type: str, slot) -> None: