Add town and currency fields to user settings

Adds two new fields to user settings form:
- Town field: Text input for city/town (required when 2D code enabled)
- Currency field: Select dropdown with ISO 4217 currency codes (EUR default)

Updates:
- Database schema: Added town and currency fields to UserSettings
- Validation: Both fields required when 2D code is enabled
- Form UI: Added input fields with proper validation and error handling
- Translations: Added Croatian and English labels and error messages
- Currency options: 36 ISO 4217 codes with EUR at top as default

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

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

messages/hr.json

@@ -191,16 +191,21 @@
     "last-name-placeholder": "Unesite svoje prezime",
     "street-label": "Ulica",
     "street-placeholder": "Unesite ulicu",
+    "town-label": "Grad",
+    "town-placeholder": "Unesite grad",
     "iban-label": "IBAN",
     "iban-placeholder": "Unesite svoj IBAN",
+    "currency-label": "Valuta",
     "save-button": "Spremi",
     "cancel-button": "Odbaci",
     "validation": {
       "first-name-required": "Ime je obavezno",
       "last-name-required": "Prezime je obavezno",
       "street-required": "Ulica je obavezna",
+      "town-required": "Grad je obavezan",
       "iban-required": "Ispravan IBAN je obavezan",
       "iban-invalid": "Neispravan IBAN format. Molimo unesite ispravan IBAN.",
+      "currency-required": "Valuta je obavezna",
       "validation-failed": "Validacija nije uspjela. Molimo provjerite formu i pokušajte ponovno."
     },
     "additional-notes": "Napomena: da bi 2D koda bio prikazan, morate unijeti i ime i prezime podstanara u postavkama svake nekretnine za koju želite koristiti ovu funkcionalnost."