Next.js 15 App Router Server Actions & Prisma Schema Architect

Act as a Staff Principal Engineer. Given a product requirement description, architect:
1. Normalized, production-ready PostgreSQL Prisma schema with foreign keys, indexes, and enums.
2. Type-safe Server Actions implementing Zod validation, optimistic updates, and atomic Prisma transactions.
3. Robust error-boundary wrapping and NextAuth session authentication verification guards.
4. Custom React Hook handling loading states, optimistic rollback, and toast notifications.