feat(alarm): trex-core 알람 emitter + trex.alerts exchange (dcy-033 BAT-049, Implemented)

AlarmEmitter(application, best-effort 비차단)+trex.alerts topic exchange 가산·격리+8 CRITICAL code 배선. 608 passed, opus QC PASS, 팀장 e2e(텔레그램 HTTP200) 통과. REQ-098~101 Implemented.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VHtM5Ws1HKCKQ4JGi6GRb5

trex_core/application/reconciliation.py

@@ -9,7 +9,9 @@ manual holds).
 from __future__ import annotations
 
 import logging
+from typing import Optional
 
+from trex_core.application.alarm_emitter import AlarmEmitter
 from trex_core.application.broker_port import BrokerPort
 from trex_core.application.portfolio import SnapshotStore
 from trex_core.domain.slot.state import SlotState
@@ -17,8 +19,14 @@ from trex_core.domain.slot.state import SlotState
 _log = logging.getLogger(__name__)
 
 
-def reconcile_core_holdings(*, slot_repo, slot_service, broker: BrokerPort,
-                           instance_key: str) -> dict[str, str]:
+def reconcile_core_holdings(
+    *,
+    slot_repo,
+    slot_service,
+    broker: BrokerPort,
+    instance_key: str,
+    alarm_emitter: Optional[AlarmEmitter] = None,
+) -> dict[str, str]:
     """dcy-020 / REQ-062 (BAT-029): surface core-slot holding ↔ broker divergence.
 
     Broker balance is the reconcile ground truth. Decisions (no silent auto-fix,
@@ -48,6 +56,13 @@ def reconcile_core_holdings(*, slot_repo, slot_service, broker: BrokerPort,
                     "core holding but broker flat: slot=%s symbol=%s -> error",
                     slot.slot_id, sym,
                 )
+                # dcy-033 / REQ-100: CRITICAL alarm — position mismatch.
+                if alarm_emitter is not None:
+                    alarm_emitter.publish_alarm(
+                        "core_holding_broker_flat",
+                        f"슬롯 보유인데 브로커 잔고 0 (slot={slot.slot_id} symbol={sym})",
+                        fields={"slot_id": str(slot.slot_id), "symbol": sym},
+                    )
             except Exception:  # noqa: BLE001 - never let reconcile crash the loop
                 _log.exception("failed to error-quarantine slot %s", slot.slot_id)
         elif slot.qty is not None and int(slot.qty) != bq:  # C — qty mismatch