Add Community Specification governance

[fkautz]

Summary

• Add the Community Specification governance policy for the SAF-K8S control catalog.
• Add Contributor Covenant 2.0 and repository-specific reporting contacts.
• Add Community Specification license acceptance, withdrawal, and patent exclusion notices.
• Link the governance and notice documents from the license, scope, and generated README.
• Update the Markdown generator so governance information and LF Projects notices remain reproducible.

Motivation

The SAF-K8S catalog is licensed under the Community Specification License 1.0 but did not include the corresponding governance, participation, and notice documents. This change documents how the Working Group operates, bounds the governed specification content, and provides the records required by the Community Specification process.

Impact

Contributors and users can now identify the Working Group's roles, decision process, scope, conduct requirements, license acceptance process, withdrawals, and patent exclusions directly from the repository. Generated README updates will preserve the governance and LF Projects references.

Validation

• Ran generate_markdown.py successfully with PyYAML 6.0.3.
• Confirmed generation changed only the expected README content.
• Ran git diff --cached --check before committing.
• Included the required DCO sign-off.