Function make_candle_callbacks 

pub fn make_candle_callbacks(
    policy: Arc<RwLock<CandleActorCritic>>,
    obs_dim: usize,
) -> (Arc<dyn Fn(&[f32]) -> (Vec<f32>, Vec<f64>) + Send + Sync>, Arc<dyn Fn(&[f32]) -> Vec<f64> + Send + Sync>)

Build action_fn and value_fn closures that read from a shared policy.

These closures are compatible with [AsyncCollector::start] and perform policy inference entirely in Rust (no GIL, no Python dispatch).