Function build_s3_client_for_compat 

async fn build_s3_client_for_compat(
    profile: &Profile,
    secret: Option<&Secret>,
) -> Client

Build an aws_sdk_s3::Client for a compat provider validation probe.

Uses the endpoint URL from compat_flags and path-style addressing. Injected credentials come from secret (manual profile) or the SDK chain.