fix: 점검 알람 컨트롤러 미디어 타입 명시적 지정

Author: kbyunghoon

monicar-control-center/src/main/java/org/controlcenter/alarm/presentation/AlarmController.java

@@ -12,6 +12,7 @@
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.data.domain.Pageable;
 import org.springframework.data.web.PageableDefault;
+import org.springframework.http.MediaType;
 import org.springframework.security.access.prepost.PreAuthorize;
 import org.springframework.security.core.annotation.AuthenticationPrincipal;
 import org.springframework.web.bind.annotation.GetMapping;
@@ -36,7 +37,7 @@ public class AlarmController implements AlarmApi {
 
 	private final AlarmService alarmService;
 
-	@GetMapping("/subscribe")
+	@GetMapping(value = "/subscribe", produces = MediaType.TEXT_EVENT_STREAM_VALUE)
 	@PreAuthorize("hasRole('ROLE_USER')")
 	public SseEmitter subscribe(@AuthenticationPrincipal CustomUserDetails user) {
 		return alarmService.subscribe(user.getId());