feat: wire attributes from RouteExecution/ProcessorExecution into storage

Replaces null placeholders with actual getAttributes() calls now that
cameleer3-common SNAPSHOT is resolved with attributes support.

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

@@ -107,7 +107,7 @@ public class IngestionService {
                 diagramHash,
                 exec.getEngineLevel(),
                 inputBody, outputBody, inputHeaders, outputHeaders,
-                null // TODO: toJson(exec.getAttributes()) — awaiting cameleer3-common publish
+                toJson(exec.getAttributes())
         );
     }
 
@@ -128,7 +128,7 @@ public class IngestionService {
                     p.getErrorMessage(), p.getErrorStackTrace(),
                     truncateBody(p.getInputBody()), truncateBody(p.getOutputBody()),
                     toJson(p.getInputHeaders()), toJson(p.getOutputHeaders()),
-                    null // TODO: toJson(p.getAttributes()) — awaiting cameleer3-common publish
+                    toJson(p.getAttributes())
             ));
             if (p.getChildren() != null) {
                 flat.addAll(flattenProcessors(