MAJOR UPPDATE: "First Ai"

feat: add AI categorization for products and enhance user management

- Integrated AI service for category suggestions in receipt import and product management.
- Added premium subscription feature for users with corresponding API endpoints.
- Implemented admin interface for managing pending product suggestions.
- Enhanced user management to include premium status and corresponding UI updates.
- Updated database schema to support new fields for premium status and product status.

backend/prisma/migrations/20260419000000_add_is_premium_and_product_status/migration.sql

@@ -0,0 +1,8 @@
+-- AlterTable User: add isPremium field
+ALTER TABLE `User` ADD COLUMN `isPremium` BOOLEAN NOT NULL DEFAULT false;
+
+-- AlterTable Product: add status field
+ALTER TABLE `Product` ADD COLUMN `status` VARCHAR(191) NOT NULL DEFAULT 'active';
+
+-- CreateIndex for status on Product (optional, for filtering pending)
+CREATE INDEX `Product_status_idx` ON `Product`(`status`);