Implements the runner case (terminal: None, no PTY) in pipe.rs:
- allocate_pipe spawns via tokio::process::Command with Stdio::piped(),
returning a TtyHandle with separate stdout/stderr (stderr=Some).
- stdin: ChildStdin boxed as Box<dyn AsyncWrite + Send + Unpin>.
- stdout/stderr: ChildStdout/ChildStderr wrapped via tokio_util::io::ReaderStream
into Pin<Box<dyn Stream<Item = Bytes> + Send>> (errors map to stream EOF).
- exit_code: PipeExitFuture holding the Child; poll drives Child::wait() and
disarms the guard on resolve; Drop calls Child::start_kill() on cancel
(ADR-056 spec-compliant kill-on-Drop, not kill_on_drop(true) alone).
- control: PipeControl (no-op resize, libc::kill(pid, sig) signal on Unix,
SIGKILL fallback for unknown names; non-Unix logs and relies on Drop guard).
Doc comment documents the no-process-group limitation of pipe mode.
Adds tokio-util (io) and tokio-stream (dev) deps. 9 unit tests cover the
happy path, stdin round-trip, separate stderr, SIGTERM signal, cancel
cleanup (asserts child killed via kill(pid,0)), resize no-op, unknown
signal SIGKILL fallback, pid recording, and empty-command error.
glm-5.2
c76b6aab7a