Promote validated community knowledge

[JesperSchulz]

The community layer contained mature rules ready for Microsoft endorsement alongside guidance whose semantics were already covered by Microsoft articles. Consolidating them reduces retrieval noise and gives review skills canonical paths and discovery signals.

What changed

• Promotes eight net-new AppSource, UI, error-handling, and security articles, including their samples.
• Removes six covered or overlapping articles while retaining the FactBox and IsTemporary guidance in the community layer.
• Corrects the Copilot help URL version gate, split-button recommendations, and version/length nuances for encrypted isolated storage.
• Updates review-skill tokens, examples, and references to match the cleaned corpus. Telemetry scope remains covered by the Microsoft privacy guidance, so the telemetry leaf now uses its empty-corpus result instead of citing the removed duplicate.

Validation

• Frontmatter and structure validator
• Deterministic knowledge-index generation with full coverage of 224 articles