fix: hourly job timeBucket 파라미터 문자열 "hourly" → 실제 시간값 전달

VesselBatchScheduler에서 hourlyAggregationJob 실행 시 timeBucket 파라미터에
"hourly" 문자열을 전달하여 HourlyTrackMergeProcessor의 LocalDateTime.parse() 실패.
startTime (정시 값)을 전달하도록 수정.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/main/java/gc/mda/signal_batch/batch/job/VesselBatchScheduler.java

@@ -162,7 +162,7 @@ public class VesselBatchScheduler {
             JobParameters params = new JobParametersBuilder()
                     .addString("startTime", startTime.toString())
                     .addString("endTime", endTime.toString())
-                    .addString("timeBucket", "hourly")
+                    .addString("timeBucket", startTime.toString())
                     .addString("executionTime", now.toString())
                     .addString("enableAbnormalDetection", String.valueOf(abnormalDetectionEnabled))
                     .toJobParameters();