Add PostgreSQL support with SQLite/Postgres database compatibility layer

- Add dbGet/dbAll helper functions for database-agnostic queries
- Add toDbBool/convertBooleansForDb for boolean type conversion
- Add toDbDate/getNow for timestamp type handling
- Add generateId that returns UUID for Postgres, nanoid for SQLite
- Update all routes to use compatibility helpers
- Add normalizeEvent to return clean number types from Postgres decimal
- Add formatPrice utility for consistent price display
- Add legal pages admin interface with RichTextEditor
- Update carousel images
- Add drizzle migration files for PostgreSQL

frontend/src/app/linktree/page.tsx

@@ -4,6 +4,7 @@ import { useState, useEffect } from 'react';
 import Link from 'next/link';
 import { useLanguage } from '@/context/LanguageContext';
 import { eventsApi, Event } from '@/lib/api';
+import { formatPrice } from '@/lib/utils';
 import { 
   CalendarIcon, 
   MapPinIcon,
@@ -100,7 +101,7 @@ export default function LinktreePage() {
                   <span className="font-bold text-primary-yellow">
                     {nextEvent.price === 0 
                       ? t('events.details.free')
-                      : `${nextEvent.price.toLocaleString()} ${nextEvent.currency}`}
+                      : formatPrice(nextEvent.price, nextEvent.currency)}
                   </span>
                   {!nextEvent.externalBookingEnabled && (
                     <span className="text-sm text-gray-400">