Run deferred/background work on Deno Deploy (Deno Queues are NOT supported - use KV + cron instead)

Documented steps

1. Auth: In-app runtime identity; no extra credential for Deno.cron or Deno KV inside deployed code.
2. Do NOT use Deno.Kv.enqueue()/listenQueue() on the current Deno Deploy - the official migration guide states Deno Queues are not supported on the new platform (they worked only on Deploy Classic).
3. Model deferred work as KV rows: await kv.set(["jobs", crypto.randomUUID()], { type: "send-email", payload, status: "pending" });
4. Process on a schedule: Deno.cron("process-jobs", "*/1 * * * *", async () => { for await (const { key, value } of kv.list({ prefix: ["jobs"] })) { if (value.status === "pending") { /* work */ await kv.set(key, { ...value, status: "done" }); } } });
5. Claim jobs with kv.atomic().check(...).set(...).commit() so slow or backed-up ticks can't double-process.
6. For sub-minute latency, run the work synchronously in the originating request handler; for true fan-out, call an external managed queue service over HTTP.
7. Monitor via the Cron tab and Logs/Traces for the processing handler.
8. Official docs: https://docs.deno.com/deploy/migration_guide/ ; https://docs.deno.com/deploy/reference/cron/ ; https://docs.deno.com/deploy/kv/operations/