Function build_pull_request_bundle 

pub fn build_pull_request_bundle(
    repo: &str,
    pr_number: u32,
    pr_metadata: &PrMetadata,
    pr_files: &[PrFile],
    pr_reviews: &[Review],
    pr_commits: &[PrCommit],
) -> EvidenceBundle

Builds an evidence bundle from a single pull request’s metadata and reviews.