Function fetch_paper_plan 

pub fn fetch_paper_plan(ref_: &Ref, store_root: &Utf8Path) -> FetchPlan

Build the dry-run preview (FetchPlan) for a single ref without touching the network, store, or provenance log. Thin re-export of crate::dry_run::build_fetch_plan under the slice-2 naming the MCP tool surfaces use; kept here so the MCP doiget_fetch_paper tool method does not have to reach across two modules.