parse cd foo && ... for exec and apply_patch (#3083)

sometimes the model likes to run "cd foo && ..." instead of using the
workdir parameter of exec. handle them roughly the same.

codex-rs/Cargo.lock

@@ -636,6 +636,7 @@ version = "0.0.0"
 dependencies = [
  "anyhow",
  "assert_cmd",
+ "once_cell",
  "pretty_assertions",
  "similar",
  "tempfile",