Function render_actor_assignments 

pub(crate) fn render_actor_assignments(
    actor_id_counter: &AtomicU32,
    worker_map: &BTreeMap<WorkerId, WorkerInfo>,
    adaptive_parallelism_strategy: AdaptiveParallelismStrategy,
    loaded: &LoadedFragmentContext,
) -> MetaResult<RenderedGraph>

Sync render stage: uses loaded fragment context and current worker info to produce actor-to-worker assignments and vnode bitmaps.