Feature Request: API DELETE Endpoint for RealtimeKit App Deletion

This feature request proposes adding a DELETE endpoint to the RealtimeKit API for programmatic app deletion. Currently, there appears to be no documented way to delete apps via the API.

### Example Request

```bash
curl -X DELETE \
https://api.cloudflare.com/client/v4/accounts/{account_id}/realtimekit/v1/apps/{app_id} \
-H "Authorization: Bearer {api_token}" \
-H "Content-Type: application/json"
```