shipping-checklist skill

# Shipping checklist — api-gateway

## Build
- [ ] tsconfig.json:14 — noEmit is true; production build needs tsc -p tsconfig.build.json (configured but not in package.json scripts)
- [x] package.json:23 — build script outputs to dist/

## Env
- [ ] src/config.ts:8 — DATABASE_URL accessed but not validated. Add zod check or fail-fast on boot.
- [ ] .env.example:11 — STRIPE_WEBHOOK_SECRET present in code (src/routes/webhook.ts:34) but missing from .env.example
- [x] src/lib/env.ts:1 — t3-env schema covers 8 of 9 required vars

## Errors
- [ ] src/routes/users.ts:42 — unhandled await on db.user.create() — wrap in try/catch and return 500 with request id
- [ ] src/middleware/error.ts:9 — error handler logs but doesn't include request id; trace correlation will fail in prod

## Monitoring
- [ ] no Sentry/observability config detected — add @sentry/node to package.json and init in src/index.ts before app.listen
- [x] src/index.ts:18 — health check endpoint at /healthz returns 200

## Deploy
- [ ] Dockerfile:11 — copies node_modules from local; should npm ci in builder stage to avoid host drift
- [x] vercel.json:3 — buildCommand and outputDirectory set

7 of 12 items pass · 5 blocking items remain · est. 35 min to clear