Function build_doctor_report 

fn build_doctor_report(
    regs: &[&(dyn Migration + Sync)],
    ctx: &MigrationContext,
    applied: &AppliedIds,
    records: &[VerifyRecord],
) -> DoctorReport

Assemble the report from an already-run verify pass, so cmd_verify can print the per-record NDJSON lines from the same records the report summarises rather than verifying twice.