fix(cli): re-raise the actual terminating signal, not always SIGINT

Addresses PR review: the handler also catches SIGTERM on non-Windows, but the exit path unconditionally re-raised SIGINT and printed a "press Ctrl-C again" hint. A SIGTERM shutdown (supervisor / container stop) would exit 130 instead of the conventional 143 and show a misleading message.

Capture which signal fired, re-raise that same signal (SIGINT→130, SIGTERM→143 via 128+signum), and tailor the first-signal message.