feat: connect application input and output boundaries

src/adapters/platform/system-clock.js

@@ -0,0 +1,19 @@
+/** @type {import("../../application/ports/clock-port.js").ClockPort} */
+export const systemClock = Object.freeze({
+  now: () => Date.now(),
+  sleep(milliseconds, signal) {
+    return new Promise((resolve, reject) => {
+      if (signal?.aborted) {
+        reject(signal.reason);
+        return;
+      }
+
+      const timer = setTimeout(resolve, milliseconds);
+      const onAbort = () => {
+        clearTimeout(timer);
+        reject(signal?.reason);
+      };
+      signal?.addEventListener("abort", onAbort, { once: true });
+    });
+  },
+});