Update formatCurrency to use currency code from UserSettings

Changes:
- Updated formatCurrency function:
  - Added currencyCode parameter with EUR default
  - Implemented Intl.NumberFormat for proper currency formatting
  - Added fallback for invalid currency codes
- Updated component hierarchy to pass currency:
  - HomePage: Fetch userSettings and pass to MonthLocationList
  - MonthLocationList: Accept and pass currency to child components
  - LocationCard: Accept currency prop and use in formatCurrency
  - MonthCard: Accept currency prop and use in formatCurrency
  - ViewLocationCard: Pass currency from userSettings to formatCurrency
- Removed hardcoded $ symbols, now using proper currency formatting

All currency amounts now display with the user's selected currency code
from their settings, using locale-appropriate formatting (hr-HR).

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

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

app/ui/HomePage.tsx

@@ -1,5 +1,6 @@
 import { fetchAllLocations } from '@/app/lib/actions/locationActions';
 import { fetchAvailableYears } from '@/app/lib/actions/monthActions';
+import { getUserSettings } from '@/app/lib/actions/userSettingsActions';
 import { BillingLocation, YearMonth } from '@/app/lib/db-types';
 import { FC } from 'react';
 import { MonthLocationList } from '@/app/ui/MonthLocationList';
@@ -33,8 +34,9 @@ export const HomePage:FC<HomePageProps> = async ({ searchParams }) => {
   }
 
   const currentYear = Number(searchParams?.year) || new Date().getFullYear();
-  
+
   const locations = await fetchAllLocations(currentYear);
+  const userSettings = await getUserSettings();
 
   // group locations by month
   const months = locations.reduce((acc, location) => {
@@ -69,7 +71,7 @@ export const HomePage:FC<HomePageProps> = async ({ searchParams }) => {
   } });
 
  return (
-    <MonthLocationList availableYears={availableYears} months={months} />
+    <MonthLocationList availableYears={availableYears} months={months} userSettings={userSettings} />
   );
 }