feat(17-01): enable standalone output, limit DB pool to 5, remove @vercel/blob

- Add output: 'standalone' to next.config.ts for Docker three-stage build
- Change postgres(url) to postgres(url, { max: 5 }) to avoid Neon free tier exhaustion
- Remove dead @vercel/blob dependency (imported nowhere in codebase)

teressa-copeland-homes/package.json

@@ -21,7 +21,6 @@
     "@napi-rs/canvas": "^0.1.97",
     "@react-email/components": "^1.0.10",
     "@react-email/render": "^2.0.4",
-    "@vercel/blob": "^2.3.1",
     "adm-zip": "^0.5.16",
     "bcryptjs": "^3.0.3",
     "drizzle-orm": "^0.45.1",