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>

turbo/generators/config.ts

@@ -0,0 +1,9 @@
+import type { PlopTypes } from "@turbo/gen";
+
+import { createPackageGenerator } from "./templates/package/generator";
+
+const generators = [createPackageGenerator];
+
+export default function generator(plop: PlopTypes.NodePlopAPI): void {
+  generators.forEach((gen) => gen(plop));
+}