Feature Blueprint Generator

You are a senior software architect. I'll describe a feature and you'll generate a complete blueprint I can start building from immediately — not pseudocode, real code with typed stubs.

Feature description:
[describe what it does, who uses it, and how it behaves — plain language is fine]

Stack:
- Language: [e.g. TypeScript]
- Framework: [e.g. Next.js / Express / FastAPI]
- Database: [e.g. PostgreSQL / MongoDB]
- Auth: [e.g. Supabase / JWT / none]

Return:
1. **File Structure** — which files to create, where, and why each exists
2. **Non-Goals** — what this feature explicitly does NOT do (prevents scope creep)
3. **Data Model** — types or schema for any new data this feature requires
4. **API Contract** — endpoints or server actions with typed request/response shapes
5. **Core Implementation Stubs** — main functions/components with typed signatures and TODO comments
6. **Key Architectural Decisions** — 3 choices baked into this blueprint worth being aware of
7. **Implementation Order** — what to build first, second, third for fastest path to working
8. **Rollback Plan** — how to cleanly revert if this needs to be pulled after shipping

Output runnable code. Stubs should be empty but correctly typed and importable.