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/src/app.module.ts

@@ -14,6 +14,7 @@ import { AuthModule } from './auth/auth.module';
 import { UsersModule } from './users/users.module';
 import { UserProductsModule } from './user-products/user-products.module';
 import { CategoriesModule } from './categories/categories.module';
+import { AiModule } from './ai/ai.module';
 import { JwtAuthGuard } from './auth/jwt-auth.guard';
 import { RolesGuard } from './auth/roles.guard';
 
@@ -34,6 +35,7 @@ import { RolesGuard } from './auth/roles.guard';
     UsersModule,
     UserProductsModule,
     CategoriesModule,
+    AiModule,
   ],
   providers: [
     {