Function run_wrapper 

pub async fn run_wrapper<E, R>(
    config: &WrapperConfig,
    env: &E,
    cache: &Arc<dyn StorageBackend>,
    runner: &R,
) -> Result<WrapperReceipt, WrapperError>
where
    E: DockerfileEnvironment,
    R: CommandRunner,

Run the wrapper: compute the graph, check the cache, and either materialize a hit or fall through to a real build.

Errors

Returns WrapperError if the Dockerfile can’t be parsed into a graph, or if the cache backend itself errors (a cache miss is not an error — only a backend I/O failure is). A failing docker build subprocess is not a WrapperError — it is the typed WrapperOutcome::BuildFailed inside an Ok receipt.