Remove lastName field from UserSettings and database

- Removed lastName from UserSettings interface
- Updated UserSettingsForm to remove lastName input field
- Removed lastName from all database operations
- Updated form validation schema to remove lastName validation
- Updated ViewLocationCard to use only firstName for recipient name
- Removed lastName from user settings form state tracking
- Updated Croatian translations to reflect changes

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

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

app/lib/actions/userSettingsActions.ts

@@ -15,7 +15,6 @@ import * as IBAN from 'iban';
 export type State = {
     errors?: {
         firstName?: string[];
-        lastName?: string[];
         street?: string[];
         town?: string[];
         iban?: string[];
@@ -31,7 +30,6 @@ export type State = {
  */
 const FormSchema = (t: IntlTemplateFn) => z.object({
     firstName: z.string().optional(),
-    lastName: z.string().optional(),
     street: z.string().optional(),
     town: z.string().optional(),
     iban: z.string()
@@ -57,15 +55,6 @@ const FormSchema = (t: IntlTemplateFn) => z.object({
     message: t("first-name-required"),
     path: ["firstName"],
 })
-.refine((data) => {
-    if (data.show2dCodeInMonthlyStatement) {
-        return !!data.lastName && data.lastName.trim().length > 0;
-    }
-    return true;
-}, {
-    message: t("last-name-required"),
-    path: ["lastName"],
-})
 .refine((data) => {
     if (data.show2dCodeInMonthlyStatement) {
         return !!data.street && data.street.trim().length > 0;
@@ -148,7 +137,6 @@ export const updateUserSettings = withUser(async (user: AuthenticatedUser, prevS
 
     const validatedFields = FormSchema(t).safeParse({
         firstName: formData.get('firstName') || undefined,
-        lastName: formData.get('lastName') || undefined,
         street: formData.get('street') || undefined,
         town: formData.get('town') || undefined,
         iban: formData.get('iban') || undefined,
@@ -165,7 +153,7 @@ export const updateUserSettings = withUser(async (user: AuthenticatedUser, prevS
         };
     }
 
-    const { firstName, lastName, street, town, iban, currency, show2dCodeInMonthlyStatement } = validatedFields.data;
+    const { firstName, street, town, iban, currency, show2dCodeInMonthlyStatement } = validatedFields.data;
 
     // Normalize IBAN: remove spaces and convert to uppercase
     const normalizedIban = iban ? iban.replace(/\s/g, '').toUpperCase() : null;
@@ -177,7 +165,6 @@ export const updateUserSettings = withUser(async (user: AuthenticatedUser, prevS
     const userSettings: UserSettings = {
         userId,
         firstName: firstName || null,
-        lastName: lastName || null,
         street: street || null,
         town: town || null,
         iban: normalizedIban,