Enables Copilot to be requested as a pull request reviewer, supporting both interactive and non-interactive flows. Introduces new reviewer search functionality, updates reviewer partitioning to distinguish users, bots, and teams, and adds a GraphQL mutation for reviewer management on github.com. Updates help text, tests, and internal APIs to support Copilot reviewer login and display names, while maintaining compatibility with GitHub Enterprise Server.
Thanks to @bagtoad, this commit refactors the argument to `NewCopilotReplacer(bool)` from being where this is used to what it effect is has.
Because there is already precedence for display name being `<login> (<name>)`, I worried there would be confusion for `Copilot (AI)` being display name for assignees and reviewers but `Copilot` when going to GitHub.com UI. Instead, I renamed the argument based on whether the login is returned / replaced.
This commit is primarily focused on fixing the existing `gh issue create` tests with the changes to the underlying queries retrieving the data for resolving metadata.
Additionally, a new test case for `gh issue create --web --assignee @copilot` was added to mirror existing tests. While exercising this capability, I found out the web UI apparently wants `copilot` instead of the `copilot-swe-agent` login, so changes to address that were a part of this commit.
