v0.2.6: fix: clean up handles in worker_threads environments to prevent aborting

When using in `worker_threads` Workers, Node.js will abort with messages like:

```
uv loop at [0x00000000] has open handles...
```

when workers are exiting or are terminated with active `DgramSocket` or `SeqpacketSocket`.

To fix this issue, we need clean up all active uv_handles in hooks registered by `napi_add_env_cleanup_hook`.