Agent Skills: repurpose-deck-from-reference

Build a new-topic PPTX by reusing an existing reference deck's template (layouts / footers / fonts / palette) while replacing all content from primary sources. Use when "this Scout deck → make a GitHub Copilot app deck", "use this deck as template for new topic", "参照デックの体裁で別内容を作る", "既存 PPTX を流用して別テーマで作り直す". Different from translation (use powerpoint-automation) and from-scratch generation.