feat: turbostarter boilerplate

Production-ready Next.js boilerplate with:
- Runtime env validation (fail-fast on missing vars)
- Feature-gated config (S3, Stripe, email, OAuth)
- Docker + Coolify deployment pipeline
- PostgreSQL + pgvector, MinIO S3, Better Auth
- TypeScript strict mode (no ignoreBuildErrors)
- i18n (en/es), AI modules, billing, monitoring

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

README.md

@@ -0,0 +1,9 @@
+<div align="center">
+
+# TurboStarter
+
+Ship your startup everywhere. In minutes.
+
+[📚 Documentation](https://www.turbostarter.dev/docs/web)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[💬 Discord](https://discord.gg/KjpK2uk3JP)&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;[🚀 Demo](https://www.demo.turbostarter.dev)
+
+</div>