Add-on/Extensions Framework Scaling for AI-DLC

The goal is to create a standard mechanism to add customer sourced rules systematically to the AI-DLC with intelligence leading the way. It would only require the modification of the core rule to implement. Here is a draft Authoring guide:

[EXTENSION-AUTHORING-GUIDE.md](https://github.com/user-attachments/files/24896381/EXTENSION-AUTHORING-GUIDE.md)