[CNCF Graduation] [Security] Publish Buildpacks Security Self-Assessment as Markdown in cncf/toc repo

[kfaseela]

Buildpacks has completed a security self-assessment and made it publicly available as a document:

• Self-assessment: https://drive.google.com/file/d/1wW7N-7ZL2x6VrcNRill8sOCEJ4YgQQ9E/view
• Based on the TAG-Security self-assessment guide: https://tag-security.cncf.io/community/assessments/guide/self-assessment/

For CNCF Graduation, security self-assessments are typically published as Markdown files in a CNCF-discoverable repository to improve transparency, long-term accessibility, and reviewability (example: cncf/toc#1986).

It would be helpful to:

• Convert the existing Buildpacks security self-assessment to a Markdown (.md) format.
• Check it into an appropriate repo (cncf/toc via PR) following established precedent.
• Link to the checked-in assessment from Buildpacks security documentation for easy discovery.

This would align Buildpacks with TAG-Security guidance and common CNCF practice, while preserving the excellent work already done in the current assessment.