Function weighted_sum_fusion 

pub fn weighted_sum_fusion(
    weighted_lists: Vec<(&str, f32, Vec<(String, f32)>)>,
    top_k: usize,
) -> Vec<FusedResult>

Weighted sum fusion

Normalizes scores from each source to [0,1] and combines with weights

Arguments

• weighted_lists - List of (source_name, weight, rankings) where rankings are (id, original_score)
• top_k - Number of results to return

Returns

Fused results sorted by combined score descending