docs: Update stale documentation - .github/skills/coding-standards/python-foundational/references/design-principles.md

[github-actions]

Stale Documentation Detected

File: .github/skills/coding-standards/python-foundational/references/design-principles.md
Current ms.date: 2026-03-27
Age: 94 days (threshold: 90 days)

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Workflow Run: https://github.com/microsoft/hve-core/actions/runs/28366291604
Detection Date: 2026-06-29

Action Required

• Review and update this documentation file
• Update ms.date frontmatter to current date
• Verify technical accuracy of content
• Close this issue manually after fixes are merged