Type Alias ChurnSpawnHook 

pub type ChurnSpawnHook = fn(&mut Command) -> Result<Output, Error>;

Function pointer signature used by set_spawn_hook to intercept the git log --numstat subprocess. Lets the CLI route long-running git log calls through its ScopedChild registry so SIGINT / SIGTERM reap the subprocess instead of leaving it running after the parent exits. See crates/cli/src/signal/ and issue #477.