feat: add multilingual support for print preview empty state

Add i18n support for empty state when no barcode data is found:

**English translations:**
- "No Barcode Data Found" 
- "No bills with 2D barcodes found for {yearMonth}"

**Croatian translations:**
- "Nema Podataka o Barkodovima"
- "Nema računa s 2D barkodovima za {yearMonth}"

**Implementation:**
- Add translation keys to messages/en.json and messages/hr.json
- Update server component to fetch empty state translations
- Use proper next-intl parameter passing for yearMonth variable
- Replace hardcoded English text with localized translations

Empty state now displays correct language based on URL locale:
- /en/print/2025/01 → English empty state message
- /hr/print/2025/01 → Croatian empty state message

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

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

messages/en.json

@@ -70,7 +70,9 @@
       "print-footer": "Generated on {date} • Evidencija Režija Print System",
       "table-header-index": "#",
       "table-header-bill-info": "Bill Information",
-      "table-header-barcode": "2D Barcode"
+      "table-header-barcode": "2D Barcode",
+      "empty-state-title": "No Barcode Data Found",
+      "empty-state-message": "No bills with 2D barcodes found for {yearMonth}"
     }
   },
   "bill-delete-form": {