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/messaging.py

@@ -79,6 +79,19 @@ class MessagingTransport(Protocol):
         Raises TransportUnavailableError if not connected."""
         ...
 
+    def publish_alarm_event(
+        self,
+        routing_key: str,
+        payload: dict,
+    ) -> None:
+        """Publish to the trex.alerts exchange (dcy-033 / REQ-099).
+
+        Best-effort: mandatory=False so an unroutable message (notifier not
+        connected) is silently dropped — no DLQ, no retry.
+        Raises TransportUnavailableError if not connected (caller must swallow).
+        """
+        ...
+
     def call_rpc(
         self,
         queue: str,