Produces a structured design specification (DESIGN.md + structural layout + Decision Trace) before any visual artifact is built — the "blueprint" phase that keeps AI-generated design from feeling templated. Use this skill whenever the user asks to design, plan, mock up, or restructure any visual output — PPT / slides / decks, landing pages, dashboards, posters, charts, infographics, marketing pages, UI components, prototypes, illustrations — even when they only say "make a slide about X" or "help me put together a page for Y". Also trigger on requests to critique or improve an existing design when the user wants a principled, spec-driven pass rather than just cosmetic tweaks. Do NOT trigger when the user has already handed you a completed DESIGN.md and only wants code implementation (defer to frontend-design or implement directly).