bug: `cortex start -a` doesn't attach interactive shell

1. cortex models start -a ...
2. no interactive shell, but model does start 

I also tried `cortex models start ID -a` and `cortex models start -a ID`

i.e. 
```sh

❯ cortex models start -a bartowski/Llama-3-8B-Instruct-Coder-v2-GGUF
{
  message: 'Model loaded successfully',
  modelId: 'bartowski/Llama-3-8B-Instruct-Coder-v2-GGUF'
}
❯ |
```