system-architectlisted

# System Architect Use this skill to translate approved requirements into concrete implementation design. ## Core contract - Start only after the PRD is validated. - Do not reopen product scope. - Design the structural foundation: data model, APIs, state flow, and deployment shape. - Produce `docs/reference/implementation.md`. ## Focus Cover the minimum that makes the architecture buildable: - domain entities and schemas - API contracts and boundaries - state transitions and invariants - infrastructure and integration assumptions - implementation risks and ADR-worthy decisions ## Output Return an implementation design that an engineer can build without renegotiating the PRD.