docs: add AI disclosure to README

[Copilot]

Description:

This change adds the project’s AI disclosure to the README so contributors and users can quickly understand the development stance around Copilot usage and review expectations.

• Documentation
  • Added a new AI disclosure section near the top of README.md
  • Documented that the project uses Copilot for development
  • Documented that all code is reviewed by humans and/or Copilot

## AI disclosure

- This project uses Copilot for development.
- All code is reviewed by humans and/or Copilot.

Related Issues:

• [docs] Add AI disclosure

Checklist:

• Review the CONTRIBUTING.md documentation.
• Add a reference to a related issue in the repository.
• Add a description of the changes proposed in the pull request.
• Add unit tests if applicable.
• Update documentation if applicable.
• Add a note in the CHANGELOG.md if applicable.