CourseMarketplace

Create a **production-ready, fully functional** course marketplace where **users can sell computer courses** (multi‑vendor). The website must be modern, responsive, and include **Student**, **Seller/Instructor**, and **Admin** panels. Include a **Cart button**, a full purchase flow, and **locked/unlocked chapter access** after purchase.

### Preferred Stack
- **Next.js 14+ (App Router) + TypeScript**
- **TailwindCSS + shadcn/ui**
- **PostgreSQL + Prisma**
- Auth: **NextAuth** (credentials + Goog