Function simulated_annealing 

pub fn simulated_annealing(
    candidates: &[Vec<Candidate>],
    weights: &[f64],
    max_luts: i64,
    max_power: f64,
    max_latency: i64,
    t_init: f64,
    t_min: f64,
    alpha: f64,
    max_iter: usize,
    seed: u64,
) -> Option<SAResult>

Run SA design-space search.

• candidates — Vec of candidate lists, one per layer
• weights — per-layer scoring weight (2.0 for critical, 1.0 otherwise)
• max_luts, max_power, max_latency — budget constraints