Function resolve_runtime_driver_contract 

pub fn resolve_runtime_driver_contract(
    provider_id: &str,
    provider_namespace: &str,
    expected: &str,
    observed: &[String],
    allow_shared_driver_upgrade: bool,
) -> Result<String>

Resolve the single runtime Driver selected by a package manifest.

Omitted and explicit shared selections accept only the shared Driver. An exact legacy <provider namespace>/driver selection may opt into the forward-compatible shared runtime Driver while manifests are migrated. A missing Driver is always fatal, as are multiple, unrelated, or reverse shared-to-legacy substitutions.