feat: add admin authentication and management features

- Implemented Prisma schema with models for AdminUser, AppSettings, and Snapshot.
- Created seed script to initialize the database with an admin user and JWT secret.
- Developed admin login page with form handling and error management.
- Added API routes for admin login, logout, change password, and JWT verification.
- Integrated Stripe for payment intent management in admin orders.
- Established middleware for protecting admin routes with JWT authentication.
- Created Zustand stores for managing persona and snapshot states.

.env.example

@@ -0,0 +1,4 @@
+# Stripe Keys
+# Get your keys from https://dashboard.stripe.com/apikeys
+NEXT_PUBLIC_STRIPE_PUBLISHABLE_KEY=pk_test_51RBtf7I7xOcO9rzigsLLK3esMLmBlJoRztbzUadPhQm7tcHQuScViFEkwdfAwDxbaqt5n8BOuJV9wRSMdn2IrxIX00lqGOOJfT
+STRIPE_SECRET_KEY=sk_test_51RBtf7I7xOcO9rzitxMqK3jnTb3SPdEbyGxGBnPccGEfrIrpiEFEOIEG2oHuTumaUejUN4FyAOBg0AVCBRn6AOKI00LeWSDC10