Besides the misleading error about submodules, the command crashes when
it runs before the first files refresh has come in: the file tree
doesn't exist yet at that point, and staging all of a tree that isn't
there dereferences a nil root node. That is easy to hit in a big repo,
where `git status` takes a moment while the panel sits there empty.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>