refactor: replace qstash with Google Cloud Tasks

src/mocks/qstash.ts

@@ -1,23 +0,0 @@
-import { SignatureError } from "@upstash/qstash";
-
-import { mock } from "bun:test";
-
-class MockQstashMessages {
-  delete = mock();
-}
-
-class MockQstashClient {
-  batchJSON = mock();
-  publishJSON = mock().mockResolvedValue({ messageId: "123" });
-  messages = new MockQstashMessages();
-}
-
-class MockQstashReceiver {
-  verify = mock();
-}
-
-mock.module("@upstash/qstash", () => ({
-  Client: MockQstashClient,
-  Receiver: MockQstashReceiver,
-  SignatureError,
-}));