Generate a pre-flight deployment checklist. Stack: [DESCRIBE — e.g. Next.js + Supabase deployed to Vercel]. Build command: [YOUR BUILD COMMAND]. Environment variables required: [LIST NAMES ONLY — no values]. Pending migrations: [DESCRIBE ANY DB OR INFRA CHANGES]. Known risks: [ANY KNOWN GOTCHAS]. Generate a checklist with: 1) Pre-deploy checks — env vars, migrations, dependencies, 2) Build verification steps, 3) Smoke tests to run after deploy — specific URLs and expected behaviour, 4) Rollback plan — exactly how to revert if something breaks, 5) Post-deploy monitoring — what to watch in the first 30 minutes. Be specific to my stack. No generic advice.