Description:

When onStart() or other startup hooks throw an error, the process exits with code 0 instead of 1. This breaks systemd's Restart=on-failure and container orchestration.

Reproduce:

app.onStart(async () => {
  throw new Error('DB connection failed');
});
app.start();

$ node index.js server
[error] DB connection failed
$ echo $?
0  # Should be 1!

Root cause:

src/app.ts:504 catches all errors but only logs them without exiting.

Fix:

Exit with code 1 when detectImport !== false. This preserves test compatibility and doesn't affect runtime route errors (which correctly return 500 responses without exiting).

I can provide a PR with tests if this approach sounds good.

Tests:

We should add a test/startup-error.js, covering different hooks.