Add setting to restrict actions to the current repo

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

If I ask copilot to pull the issues, or create a new issue, it is possible that it uses the wrong owner / repo and pull random issues or tries to create issues on non-existing repos.

Then after an error, it runs `git remote -v` or calls the tool `get_me` and re-does the action.

For now, it never happened that it created issues on other people repos, but it would like to exclude the possibility entirely.

### Proposed solution

Add a setting to restrict all actions to the current repo.
This would remove the "owner" and "repo" from all tool calls.

### Example prompts or workflows (for tools/toolsets only)

### Additional context

For example, the "add comment to issue" tool would become:

```
{
"body": "....",
"issue_number": 109
}
```