backend-buildlisted

Turn the design file's `## Architecture` section into a working backend. Read it first, follow its decisions, don't invent architecture it didn't decide. ## Example prompts - "Build the backend from the brief" - "Implement the notifications service" - "Code the API defined in the design file" - "Start building the server for checkout" ## Prerequisites - A filled `## Architecture` section in the feature's design file. Find the feature's design file by the procedure in `${CLAUDE_SKILL_DIR}/../design/SKILL.md` → **Finding the design file**. In a legacy six-file folder that section is `BACKEND_DESIGN.md`. Write back only into the file you found, under the name it already has. - If none exists, stop and tell the user to run `/backend-design` first — this skill needs a brief, not a vibe. ## Process 1. **Read the brief in full.** Note every decision the brief locked in: - Stack (Fastify vs other), schema strategy (JSON Schema / TypeBox / Zod), ORM, datastore - Plugin boundaries, decorators, hooks - Auth model, error shape, logger config - Every route in the API surface table - Deployment target, migrations strategy 2. **Scan the codebase.** If this is an existing project, do NOT restart from scratch. Extend what's there. Check: - `package.json` for existing deps - Existing plugin tree, route files, decorator definitions - Existing DB connection, migration setup, test framework - `.env` / `env.example` for existing config keys 3. **State the build p