feat: add Order entity, repository, and service with TDD tests
- Create V5__create_orders_table.sql migration with orders table
- UUID primary key, user_id FK to users, status CHECK constraint
- Indexes on user_id and status columns
- Add OrderStatus enum (PENDING_PAYMENT, PAID, LOOKUP_STARTED, SENT, DELIVERED, FAILED)
- Add OrderStatusConverter for JPA VARCHAR persistence
- Create Order entity with fields: id, userId, plate, template, letterText, status, amountPaid, trackingId, timestamps
- Create OrderRepository with findByUserIdOrderByCreatedAtDesc and findByStatus queries
- Create OrderService with createOrder (normalizes plate, sets PENDING_PAYMENT), getOrdersByUserId, getOrderById
- Add OrderNotFoundException with 404 handler in GlobalExceptionHandler
- Write OrderServiceTest with 8 unit tests covering status, UUID generation, plate normalization, and error handling
Joakim Mörling
a74bb89824