Feature Request: GitHub Copilot integration for Theia IDE

### Context GitHub Copilot is widely adopted in Visual Studio Code and other IDEs, but currently not supported in Theia. ### Motivation Theia is used in cloud-based and enterprise environments where extensibility and flexibility are critical. Many developers rely on Copilot for AI-assisted code completion, and having this functionality in Theia would significantly improve productivity and user experience. ### Proposal Explore the possibility of integrating GitHub Copilot into Theia. This could be achieved by: - Leveraging Theia’s compatibility with VS Code extensions. - Collaborating with GitHub to enable official support. - Providing documentation or examples for community-driven integration. ### Expected Impact - Intelligent code completion and suggestions within Theia. - Increased adoption of Theia among developers who depend on Copilot. - Alignment with modern AI-assisted development workflows.