Add Next.js SaaS Boilerplate to Boilerplates section

[habibjutt]

Hi! I'd like to add Next.js SaaS Boilerplate to the Boilerplates section.

It's an open-source Next.js 16 starter kit built for shipping SaaS products. Here's what it includes:

• Auth: Email/password, OAuth (Google, GitHub, Apple), two-factor authentication — all powered by Better Auth
• Payments: Stripe integration with subscriptions, one-time payments, and a customer portal
• Admin dashboard: User management, role-based access control, analytics
• Blog CMS: MDX-based content management with categories and SEO
• Email system: Transactional emails via Resend with React Email templates
• UI: 50+ components built on shadcn/ui and Tailwind CSS
• Database: Prisma ORM with PostgreSQL

The repo has been actively maintained and follows the existing list format. Let me know if any changes are needed!