Feature Request: Add Pull Request (PR) Integration to LazyGit

### Describe the feature you'd like

I recently started using Neovim and switched over from VS Code. One of the features I really enjoyed in VS Code was its built-in source control view, especially how it handled GitHub pull requests directly within the editor.

When I discovered LazyGit, it instantly became my go-to tool — it’s lightweight, intuitive, and honestly even more enjoyable to use than VS Code’s source control. The only thing I’ve found missing is the ability to **interact with pull requests directly from LazyGit**.

It would be amazing to have PR-related features like:

* Viewing open pull requests in the current repo
* Checking out a PR branch
* Creating a new PR from the current branch
* Viewing PR status, comments, and merge conflicts

Having this integrated into LazyGit would make it a truly complete Git experience within the terminal.

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### Describe alternatives you've considered

I’ve tried using `gh` (the GitHub CLI) alongside LazyGit to manage PRs, but switching contexts breaks the otherwise smooth, single-interface workflow LazyGit provides. A built-in (or even optional) PR integration would make the experience seamless.

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### Additional context

This could work either through direct GitHub/GitLab API integration or via external tools like `gh` — maybe LazyGit could detect if `gh` is installed and use it under the hood.

I know there are ways to add custom commands, but having native support for PR operations would make it accessible to more users out of the box and strengthen LazyGit’s position as a complete terminal Git UI.

Thanks for all the work you’ve put into this project — it’s seriously one of the best developer tools I’ve come across!