fix: add parent field to NodeView test helper in hivectl

dag_progress.rs's test-only node() constructor was missing the new
parent field added to NodeView in hive-sh4re. Add parent: None to
silence the missing-field compile error.

hivectl/src/dag_progress.rs

@@ -323,6 +323,7 @@ mod tests {
     fn node(id: u64, agent: &str, kind: &str, state: State) -> NodeView {
         NodeView {
             id,
+            parent: None,
             agent: agent.to_owned(),
             kind: kind.to_owned(),
             deps: if id == 0 { vec![] } else { vec![id - 1] },