Function snapshot_controls 

pub fn snapshot_controls(component: &Arc<RwLock<Component>>) -> ControlMap

Snapshot the controls visible from component (its own controls plus any Subtree-scoped ancestor control, nearest-wins) into a lock-free ControlMap. Deadlock-safe: Component::control_snapshot acquires one tier’s lock at a time, never nested — so it is safe on the cadence-contended component tree. Computed once per phase, shared across the phase’s fibers.