docs(AI): Implement a formal AI policy

[mOctave]

Documentation / Policy

This PR addresses the issue of vibecoding.

Checklist

• I have read and understand the Contributing Guidelines.
• I accept the terms of the AGPL-3-or-later license of this project, and recognize that, if and when this pull request is merged, I relinquish individual ownership of my work.
• I did not use generative AI to write any code or create any other part of this PR.

Summary

This PR adds a much fuller and slightly more permissive AI Policy that can also be accessed through a symlink at AGENTS.md to make it enforceable for contributors using AI agents.

Usage examples

Automatic. Try to prompt an AI agent to make stuff and it should refer you to the AI policy and refuse to make changes. Try to ask it for help understanding stuff and it should explain it.

Testing

Tested with Cursor, seemed to respect it mostly.

Performance Impact

N/A