- Changed default download location to assets_downloaded/schematron
- Updated all references in SchematronDownloader, integration, and validator
- Updated postinstall scripts to use new location
- assets_downloaded/ is already in .gitignore to exclude downloaded files from git
- Moved existing downloaded files to new location
- All functionality tested and working correctly
- Added validation types for EN16931 compliance in `validation.types.ts`, including interfaces for `ValidationResult`, `ValidationOptions`, and `ValidationReport`.
- Introduced `VATCategoriesValidator` in `vat-categories.validator.ts` to validate VAT categories according to EN16931 rules, including detailed checks for standard, zero-rated, exempt, reverse charge, intra-community, export, and out-of-scope services.
- Enhanced `IEInvoiceMetadata` interface in `en16931-metadata.ts` to include additional fields required for full standards compliance, such as delivery information, payment information, allowances, and charges.
- Implemented helper methods for VAT calculations and validation logic to ensure accurate compliance with EN16931 standards.
