Function node_span 

pub fn node_span(
    run_id: &str,
    plan_id: &str,
    phase: &str,
    node_id: &str,
    controller_id: &str,
) -> Span

Build the per-node span (ADR-12), nested under the current phase span so node telemetry is attributed to its run, plan and controller. Identifiers only.