Function cleanup_failed_clone_dest 

pub fn cleanup_failed_clone_dest(dest: &Path, cleanable: bool)

Best-effort cleanup of a failed clone’s partial dest (R7) — call only on the clone’s error path, passing cleanable as computed by clone_dest_cleanable before the clone ran. A no-op when cleanable is false (never touches a non-empty pre-existing dest). Swallows a remove_dir_all failure (e.g. another process holding a file open) — this is opportunistic tidy-up, not something a clone failure should itself fail on.