Add AI coding agent guidelines and update permissions documentation

[Mike29CZ]

Introduce a new guide for AI coding agents in the GitHub Docs codebase and update the permissions section to include discussions. Additionally, clean up the settings.json file by removing empty changes and adding a spell check configuration.

[welcome]

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[github-actions]

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[github-actions]

👋 Hey there spelunker. It looks like you've modified some files that we can't accept as contributions:

• .github/copilot-instructions.md

You'll need to revert all of the files you changed that match that list using GitHub Desktop or git checkout origin/main <file name>. Once you get those files reverted, we can continue with the review process.

The complete list of files we can't accept are:

• .devcontainer/**
• .github/**
• data/reusables/rai/**
• Dockerfile*
• src/**
• package*.json
• content/actions/how-tos/security-for-github-actions/security-hardening-your-deployments/**

We also can't accept contributions to files in the content directory with frontmatter type: rai or contentType: rai.

[Sharra-writes]

@Mike29CZ Thanks for opening a PR! Unfortunately, this isn't an article we need, and external contributors can't alter json files, or any files other than markdown files in certain folders. If you need more information on how to contribute and what contributions we accept, see our CONTRIBUTING.md.

[Mike29CZ]

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