Clean up obsolete resources and update documentation

- Remove all DynamoDB-related scripts and data files
- Remove AWS SDK dependencies from scripts
- Update environment files to remove DynamoDB/Lambda references
- Update PROJECT_STRUCTURE.md to reflect current architecture
- Clean up Terraform variables and examples
- Add PLA Matte to special pricing (3999 RSD / 3499 RSD refill)
- Make all table columns sortable
- Remove old Terraform state backups
- Remove temporary data import files

.env.production

@@ -4,6 +4,3 @@ NODE_ENV=production
 # API Configuration
 NEXT_PUBLIC_API_URL=https://api.filamenteka.rs/api
 
-# AWS Configuration (for reference - no longer used)
-# AWS_REGION=eu-central-1
-# DYNAMODB_TABLE_NAME=filamenteka-filaments