Function run_explore_pipeline 

pub fn run_explore_pipeline(
    input: &Path,
    out: Option<PathBuf>,
    tokens: u32,
    layouts_csv: &str,
    skip_convert: bool,
    sweep_ffn_f16: bool,
    modes_csv: Option<&str>,
) -> Result<(), String>

Phase-0 explorer: convert missing layouts if source is GGUF, measure decode-proxy, rank, write JSON.

This is the decision engine for “which approach to go with” on a given host/model — not a second decoder. See docs/plans/native-inference-explorer-eval-plan.md.