watchpr only reported meaningful changes as transitions from the poll
baseline. A PR already merged or closed when the watch started was
captured as the baseline and never produced a transition, so the loop
polled the dead PR forever (process alive, never exiting) -- the
single-PR --interval case observed in production.
Add a terminal-state check applied to the baseline snapshot: a PR that
is already merged or closed the moment watchpr starts is reported and
exits immediately, since it can never change again. Extract the
baseline+poll loop into agent.Watch behind a StateFetcher interface so
the loop, its open->merged/close detection, and its poll-error
resilience are unit-testable with a fake client.
unkin-agent