Type ambiguity between docs and actual framework code.

### Existing documentation URL(s)

https://developers.cloudflare.com/agents/api-reference/queue-tasks/#getqueue
https://developers.cloudflare.com/agents/api-reference/queue-tasks/#getqueues

### What changes are you suggesting?

The queue method is defined with a generic type parameter T, suggesting it should handle and return items of that type. However, the actual return type is always QueueItem, regardless of the specified T. This means the generic typing on the method isn't propagated to the QueueItem return value.

### Additional information

Agent version: 0.7.2
Wrangler version: 4.69.0