Refactor event handling and user management: Replace direct database calls with service layer methods for events, user profiles, and preferences, enhancing code organization and maintainability. Update API routes to utilize new services for event registration, feedback, and user statistics, ensuring a consistent approach across the application.

app/admin/page.tsx

@@ -1,6 +1,6 @@
 import { redirect } from "next/navigation";
 import { auth } from "@/lib/auth";
-import { prisma } from "@/lib/prisma";
+import { sitePreferencesService } from "@/services/preferences/site-preferences.service";
 import { Role } from "@/prisma/generated/prisma/client";
 import NavigationWrapper from "@/components/NavigationWrapper";
 import AdminPanel from "@/components/AdminPanel";
@@ -18,22 +18,9 @@ export default async function AdminPage() {
     redirect("/");
   }
 
-  // Récupérer les préférences globales du site
-  let sitePreferences = await prisma.sitePreferences.findUnique({
-    where: { id: "global" },
-  });
-
-  // Si elles n'existent pas, créer une entrée par défaut
-  if (!sitePreferences) {
-    sitePreferences = await prisma.sitePreferences.create({
-      data: {
-        id: "global",
-        homeBackground: null,
-        eventsBackground: null,
-        leaderboardBackground: null,
-      },
-    });
-  }
+  // Récupérer les préférences globales du site (ou créer si elles n'existent pas)
+  const sitePreferences =
+    await sitePreferencesService.getOrCreateSitePreferences();
 
   return (
     <main className="min-h-screen bg-black relative">