[gabemule]

Why

Finding L-1 from the architect's review of #5. In 0.2.0, waitExit unref'd its grace timer, and opencode serve is unref'd too. So once a host had closed its own handles, nothing held the event loop and the process exited before shutdown() settled:

• code after await shutdown() never ran;
• a signal handler's own exit code was lost (0 instead of 130);
• a process ignoring SIGTERM never got the SIGKILL.

What

• timer.unref() is removed from waitExit. The timer is cleared as soon as every pending process has exited, so the loop is held only while something is left to wait for. The longest it can be held is graceMs plus 1 s, which the README now states.
• Two child-script tests, each run with a child that obeys SIGTERM and one that ignores it:
  • a top-level await shutdown();
  • a SIGINT handler that clears its own timer, then await shutdown(), then a log line, then exit(130).

Verified locally

• Node 24 and Node 22: 170/170. Bun 1.3.14: 160 pass, 0 fail. verify:pack ok.
• With unref restored, 4 tests go red on Node and 2 on Bun (the handler shape: the top-level shape does not trip Bun). With the fix, all are green.
• After a script awaits shutdown() with nothing pending, the process exits within ordinary runtime start-up time (about 100 to 280 ms), never after the 3 s grace.
• No orphaned processes after the runs.