Function build_ruby_frontend_run 

pub fn build_ruby_frontend_run(
    manifest: &CoverageManifest,
    evidence_directory: &Path,
    run_id: &str,
    generated_at: &str,
    test_exit_code: i32,
    assertions: &RubyAssertionInventory,
) -> Result<RubyFrontendRun, RubyEvidenceError>

Join the runtime’s evidence directory with the ahead-of-run manifest into a protocol-conformant frontend run.