Add Initial Copilot instructions for editor-api

[adrian-rpf]

Status

• Gives a first draft of a copilot instructions to help improve the usefulness of GH Copilot

Points for consideration:

✅ - Security - repo only document
✅ - Performance - repo only document

What's changed?

• Creation of a new copilot instructions file.

Steps to perform after deploying to production

✅ - no deployments requirement

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have you on file. In order for us to review and merge your code, please complete this form and we'll get you added and review your contribution as soon as possible.

[Copilot]

Pull Request Overview

This PR introduces initial Copilot instructions for the editor-api repository to help GitHub Copilot provide more useful and context-aware assistance to developers working on this Rails 7.1 application that exposes REST and GraphQL APIs for educational coding features.

• Adds comprehensive documentation of the application's architecture, authentication/authorization patterns, and domain boundaries
• Provides developer workflow guidelines including Docker-based setup, testing, and deployment procedures
• Documents key conventions, environment variables, and code examples to guide AI-assisted development

---

_{Tip: Customize your code reviews with copilot-instructions.md. Create the file or learn how to get started.}

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have you on file. In order for us to review and merge your code, please complete this form and we'll get you added and review your contribution as soon as possible.

[cla-bot]

We require contributors to sign our Contributor License Agreement, and we don't have you on file. In order for us to review and merge your code, please complete this form and we'll get you added and review your contribution as soon as possible.