fix: detect replay via replayExchangeId field, not just header

The X-Cameleer-Replay header is only available when inputSnapshot is
captured (DETAILED/DEEP engine level). The agent always sets
replayExchangeId on RouteExecution, so check that first.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

cameleer3-server-core/src/main/java/com/cameleer3/server/core/ingestion/IngestionService.java

@@ -102,8 +102,8 @@ public class IngestionService {
 
         boolean hasTraceData = hasAnyTraceData(exec.getProcessors());
 
-        boolean isReplay = false;
-        if (inputSnapshot != null && inputSnapshot.getHeaders() != null) {
+        boolean isReplay = exec.getReplayExchangeId() != null;
+        if (!isReplay && inputSnapshot != null && inputSnapshot.getHeaders() != null) {
             isReplay = "true".equalsIgnoreCase(
                     String.valueOf(inputSnapshot.getHeaders().get("X-Cameleer-Replay")));
         }