Function collect_release_repo_evidence 

pub fn collect_release_repo_evidence(
    client: &GitHubClient,
    owner: &str,
    repo: &str,
    head_tag: &str,
    bundle: &mut EvidenceBundle,
)

Phase 2: Collect repository security posture and merge into the bundle.

Queries branch protection, secret scanning, code scanning, CODEOWNERS, workflow permissions, tag protection rules, etc.