feat: support iteration wrapper nodes and filter overlay by selected iteration

Server:
- Add split_depth and loop_depth columns (V9 migration)
- Persist splitDepth/loopDepth with reflection fallback for older agent versions

UI:
- Detect iterations via wrapper processorTypes (loopIteration, splitIteration, multicastBranch)
- Filter overlay by selected iteration at the wrapper level
- Skip non-selected iteration wrappers entirely (wrapper + children)
- Don't add synthetic wrappers to overlay (no diagram node correspondence)

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

@@ -132,7 +132,9 @@ public class IngestionService {
                     p.getLoopIndex(), p.getLoopSize(),
                     p.getSplitIndex(), p.getSplitSize(),
                     p.getMulticastIndex(),
-                    p.getResolvedEndpointUri()
+                    p.getResolvedEndpointUri(),
+                    getDepthSafe(p, "splitDepth"),
+                    getDepthSafe(p, "loopDepth")
             ));
             if (p.getChildren() != null) {
                 flat.addAll(flattenProcessors(
@@ -143,6 +145,16 @@ public class IngestionService {
         return flat;
     }
 
+    /** Safely call getSplitDepth()/getLoopDepth() — returns 0 if not available in this cameleer3-common version. */
+    private static int getDepthSafe(ProcessorExecution p, String field) {
+        try {
+            var method = p.getClass().getMethod("get" + Character.toUpperCase(field.charAt(0)) + field.substring(1));
+            return (int) method.invoke(p);
+        } catch (Exception e) {
+            return 0;
+        }
+    }
+
     private String truncateBody(String body) {
         if (body == null) return null;
         if (body.length() > bodySizeLimit) return body.substring(0, bodySizeLimit);

cameleer3-server-core/src/main/java/com/cameleer3/server/core/storage/ExecutionStore.java

@@ -39,6 +39,8 @@ public interface ExecutionStore {
             Integer loopIndex, Integer loopSize,
             Integer splitIndex, Integer splitSize,
             Integer multicastIndex,
-            String resolvedEndpointUri
+            String resolvedEndpointUri,
+            int splitDepth,
+            int loopDepth
     ) {}
 }