Fix 03-workload-ai-hpc

```
    for i, task in enumerate(results):
        rtype = "AI" if "prompt" in task else "Compute"
        print(f"Task {i + 1} [{rtype}] ({task.get('backend')}): {task.return_value}", flush=True)
```

Instead, it should be:

```
 print(f"Task {i + 1} [{rtype}] ({task.get('backend')}): {task.stdout if task.stdout else task.response}", flush=True)
```