Remove otvoreno field references from all test files

- Updated ui-features.test.ts to remove otvoreno field expectations
- Updated api-integration.test.ts to remove otvoreno from test data
- Updated data-consistency.test.ts to remove otvoreno from structure definitions
- Updated filament-crud.test.ts to remove otvoreno from CRUD operations
- Updated quantity calculations to only use refill and vakuum fields

All tests pass after these changes.

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

__tests__/api-integration.test.ts

@@ -43,7 +43,6 @@ describe('API Integration Tests', () => {
         boja_hex: '#000000',
         refill: '2',
         vakum: '1 vakuum',
-        otvoreno: 'Ne',
         kolicina: '3',
         cena: '3999'
       };
@@ -88,7 +87,6 @@ describe('API Integration Tests', () => {
         boja_hex: '#1E88E5',
         refill: '3',
         vakum: '2 vakuum',
-        otvoreno: '1 otvorena',
         kolicina: '6',
         cena: '4500'
       };