Identify CELA Guidance for 3rd Party Extensions

## Description

Document compliance requirements and legal review process for 3rd party extensions. Work with CELA (Corporate, External, and Legal Affairs) to establish clear guidance for extension authors.

## Acceptance Criteria

- Documented compliance requirements for 3rd party extensions
- Defined legal review process and workflow
- Approval workflow documented
- Licensing requirements specified
- Terms of service and acceptable use policies defined
- Clear documentation accessible to extension authors
- CELA sign-off on guidance

## Key Areas to Document

- Legal review triggers and requirements
- License compatibility (extension licenses vs. azd license)
- Intellectual property considerations
- Open source compliance requirements
- Third-party dependency review
- Export compliance considerations

## Parent Issue

This is part of the 3rd Party Extension Submission Process epic.

## Labels

extensions, compliance, documentation