boot() asserts over ctx.loader after awaiting the Loader, but the TUI renders
as soon as its own fiber starts: an /exit typed before the last entry settles
runs disposeRootAndExit, which takes the Loader service with the tree. The
assertions then read undefined and crashed the process with a TypeError over
an app that exited exactly as asked. The keyless personal-overlay PTY smoke
lost this race in roughly two of three runs.