refactor: modularize cli helpers

src/cli/wait.ts

@@ -0,0 +1,8 @@
+export function waitForever() {
+	// Keep event loop alive via an unref'ed interval plus a pending promise.
+	const interval = setInterval(() => {}, 1_000_000);
+	interval.unref();
+	return new Promise<void>(() => {
+		/* never resolve */
+	});
+}