feat(core-testing): RecordingJobQueue

Adds RecordingJobQueue implementing IJobQueue for use in unit tests.
Records all enqueue calls with taskSlug/input/options and returns
synthetic incrementing jobIds.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/core-testing/src/instrumentation/index.ts

@@ -1,2 +1,3 @@
 export { RecordingTracer, type RecordedSpan } from "./recording-tracer";
 export { RecordingLogger, type RecordedCapture } from "./recording-logger";
+export { RecordingJobQueue } from "./recording-job-queue";