Use unshare by default in linux to protect access

### Describe the feature or problem you'd like to solve

The tool should never have any kind of write access to places the users have not ack'ed for

### Proposed solution

I'm currently running copilot using bubblewrap to ensure it only works where I want via:

```sh
bwrap --ro-bind / / \
--bind "$PWD" "$PWD" \
--bind /tmp /tmp \
--bind "$HOME/.copilot" "$HOME/.copilot" \
--dev /dev \
--proc /proc \
--unshare-all \
copilot
```

This is something that the tool should do by default

### Example prompts or workflows

_No response_

### Additional context

_No response_