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-app/src/main/java/com/cameleer3/server/app/storage/PostgresExecutionStore.java

@@ -74,8 +74,8 @@ public class PostgresExecutionStore implements ExecutionStore {
                     status, start_time, end_time, duration_ms, error_message, error_stacktrace,
                     input_body, output_body, input_headers, output_headers, attributes,
                     loop_index, loop_size, split_index, split_size, multicast_index,
-                    resolved_endpoint_uri)
-                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?::jsonb, ?::jsonb, ?::jsonb, ?, ?, ?, ?, ?, ?)
+                    resolved_endpoint_uri, split_depth, loop_depth)
+                VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?, ?::jsonb, ?::jsonb, ?::jsonb, ?, ?, ?, ?, ?, ?, ?, ?)
                 ON CONFLICT (execution_id, processor_id, start_time) DO UPDATE SET
                     status = EXCLUDED.status,
                     end_time = COALESCE(EXCLUDED.end_time, processor_executions.end_time),
@@ -92,7 +92,9 @@ public class PostgresExecutionStore implements ExecutionStore {
                     split_index = COALESCE(EXCLUDED.split_index, processor_executions.split_index),
                     split_size = COALESCE(EXCLUDED.split_size, processor_executions.split_size),
                     multicast_index = COALESCE(EXCLUDED.multicast_index, processor_executions.multicast_index),
-                    resolved_endpoint_uri = COALESCE(EXCLUDED.resolved_endpoint_uri, processor_executions.resolved_endpoint_uri)
+                    resolved_endpoint_uri = COALESCE(EXCLUDED.resolved_endpoint_uri, processor_executions.resolved_endpoint_uri),
+                    split_depth = EXCLUDED.split_depth,
+                    loop_depth = EXCLUDED.loop_depth
                 """,
                 processors.stream().map(p -> new Object[]{
                         p.executionId(), p.processorId(), p.processorType(),
@@ -105,7 +107,9 @@ public class PostgresExecutionStore implements ExecutionStore {
                         p.attributes(),
                         p.loopIndex(), p.loopSize(), p.splitIndex(), p.splitSize(),
                         p.multicastIndex(),
-                        p.resolvedEndpointUri()
+                        p.resolvedEndpointUri(),
+                        p.splitDepth(),
+                        p.loopDepth()
                 }).toList());
     }
 
@@ -164,7 +168,9 @@ public class PostgresExecutionStore implements ExecutionStore {
                     rs.getObject("split_index") != null ? rs.getInt("split_index") : null,
                     rs.getObject("split_size") != null ? rs.getInt("split_size") : null,
                     rs.getObject("multicast_index") != null ? rs.getInt("multicast_index") : null,
-                    rs.getString("resolved_endpoint_uri"));
+                    rs.getString("resolved_endpoint_uri"),
+                    rs.getInt("split_depth"),
+                    rs.getInt("loop_depth"));
 
     private static Instant toInstant(ResultSet rs, String column) throws SQLException {
         Timestamp ts = rs.getTimestamp(column);

cameleer3-server-app/src/main/resources/db/migration/V9__resolved_endpoint_uri.sql

@@ -1 +1,3 @@
 ALTER TABLE processor_executions ADD COLUMN resolved_endpoint_uri TEXT;
+ALTER TABLE processor_executions ADD COLUMN split_depth INTEGER DEFAULT 0;
+ALTER TABLE processor_executions ADD COLUMN loop_depth INTEGER DEFAULT 0;