Allow to pass data to stdin while providing a prompt

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

Allow to pass data to stdin while providing a prompt

### Proposed solution

This is actually mentioned in #96, but the use-case of passing data to stdin doesn't seem to be implemented.

I would like to pass data as stdin to copilot and provide a prompt about what to do with this data. This opens a lot of possibilities of having copilot do things non-interactive with data you pass to it.

When I try to pass data to stdin, it seems to ignore this. It is mentioned in the copliot cli docs that you can pass "options", but i'm not sure if this means data.

### Example prompts or workflows

* checking a diff
```sh
$ git diff | copilot -p "can you take a look at this diff to see if it seems correct?"
```

* generate a one-liner for a diff for a commit message
```sh
$ git diff | copilot -p "can you tell me in one sentence what this diff changes?"
```

* checking for kernel issues
```sh
$ dmesg | tail -n 100 | copilot -p "my pc seems to hang, can you spot why by looking at this dmesg"
```

* lots of other things, checking logfiles, generating a table from a json file, ...

### Additional context

_No response_