Produce a director-readable system design pack — architecture diagrams (models, external services, re-ranking/AI gateways, infrastructure topologies) plus workflow sequence diagrams — as a white-theme zoomable HTML viewer and a prose companion. Use for existing codebases (reverse-engineer) or greenfield projects (design before build). Triggers: "system design", "architecture diagram", "how does this system work", "model wiring", "infra diagram", "flow diagram", "visual architecture", "zoomable architecture", or the skill name director-02-system-design. Complements director-02-app-blueprint (screens/UX); this skill covers technical system architecture, not screen maps.
