Vibe Coding — Backend Structure Generator

Generate BACKEND_STRUCTURE.md. Every data model and API endpoint documented with exact types and contracts.

Prerequisites Check

1. Read progress.txt — check has_frontend: false flag
2. Read ./docs/PRD.md — features determine data models
3. Read ./docs/APP_FLOW.md — screens determine API endpoints
4. Read ./docs/TECH_STACK.md — detect ORM and API style:

Frontend-only project (no backend in TECH_STACK.md) → READ: ## Frontend-Only Handler