Rename tenantFirstName to tenantName with updated validation

- Renamed tenantFirstName to tenantName in BillingLocation interface
- Updated LocationEditForm field to accept full name (first and last)
- Set maximum length to 30 characters for tenant name field
- Updated all database operations to use tenantName
- Changed English label from "Tenant First Name" to "Tenant First and Last Name"
- Updated Croatian translations to match (Ime i prezime podstanara)
- Updated form validation schema and error messages
- Removed old tenantLastName-related translations

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

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

app/ui/ViewLocationCard.tsx

@@ -16,7 +16,7 @@ export interface ViewLocationCardProps {
 
 export const ViewLocationCard:FC<ViewLocationCardProps> = ({location, userSettings}) => {
 
-    const { _id, name, yearMonth, bills, tenantFirstName, tenantStreet, tenantTown } = location;
+    const { _id, name, yearMonth, bills, tenantName, tenantStreet, tenantTown } = location;
 
     const t = useTranslations("home-page.location-card");
 
@@ -25,7 +25,7 @@ export const ViewLocationCard:FC<ViewLocationCardProps> = ({location, userSettin
 
     const paymentParams:PaymentParams = {
         Iznos: (monthlyExpense/100).toFixed(2).replace(".",","),
-        ImePlatitelja: tenantFirstName ?? "",
+        ImePlatitelja: tenantName ?? "",
         AdresaPlatitelja: tenantStreet ?? "",
         SjedistePlatitelja: tenantTown ?? "",
         Primatelj: (userSettings?.firstName && userSettings?.lastName) ? `${userSettings.firstName} ${userSettings.lastName}` : "",