Function probe_local 

pub fn probe_local(
    ctx: &Context,
    skip_mount: bool,
    data_path_override: Option<PathBuf>,
    libtorch_path_override: Option<PathBuf>,
    via_docker: Option<String>,
    data_path_explicit: bool,
) -> ProbeReport

Probe the local host. data_path_override (from --data-path CLI flag) overrides config; skip_mount short-circuits the shared-data check (useful for single-host setups without a shared FS configured); libtorch_path_override (from --libtorch-path) points at a libtorch install outside the project tree (used by cluster-mode remote probes where libtorch lives on a dedicated share like /mnt/libtorch). via_docker (from --docker <svc> or the cluster.yml host’s docker: field) tells the probe NCCL ships inside a container image, so host-level NCCL scanning is replaced by an informational “via Docker image <svc>” line.

data_path_explicit: when true, a missing shared-data path is an ERROR (the user/cluster.yml promised it); when false, it’s a WARNING (the convention default was used). Internal flag — callers must derive it from “did the caller pass an explicit data_path”.