Review of the previous commit found two defects in the release path, both
reproduced against the implementation:
- The timeout guarding a never-settling release was unref'ed. An
unhandledRejection listener suppresses Node's default fatal exit, so with
nothing else referenced the process reached an empty event loop and exited
0 on the very failure it was reporting. Keep the timer referenced and clear
it once the race settles.
- The handler uninstalled itself before awaiting the release. A second
concurrent rejection then became uncaught and killed the process
mid-teardown, stranding exactly the terminal state this restores. Replace
the uninstall with a latch: the first rejection is the reported one, and
later rejections (teardown's own included) fall through to the pending exit.
Add the PTY regression the fake-process tests cannot express: boot the shipped
tree over a fixture whose llm-pi-ai providers value is list-shaped, expect exit
1, and assert the captured bytes carry both the diagnostic and ESC[?2004l.
Against the pre-fix source the stream ends at ESC[?2004h ESC[>7u ESC[?u ESC[c
with no reset and the case fails, so it pins the actual bug.
Split the two-shape formatting test into one install per case; a latched
handler reports once by design.