Refactor admin actions and improve code formatting: Standardize import statements, enhance error handling messages, and apply consistent formatting across event, user, and preference management functions for better readability and maintainability.

app/api/register/complete/route.ts

@@ -29,17 +29,14 @@ export async function POST(request: Request) {
     });
   } catch (error) {
     console.error("Error completing registration:", error);
-    
-    if (
-      error instanceof ValidationError ||
-      error instanceof ConflictError
-    ) {
+
+    if (error instanceof ValidationError || error instanceof ConflictError) {
       return NextResponse.json({ error: error.message }, { status: 400 });
     }
     if (error instanceof NotFoundError) {
       return NextResponse.json({ error: error.message }, { status: 404 });
     }
-    
+
     return NextResponse.json(
       {
         error: `Erreur lors de la finalisation de l'inscription: ${error instanceof Error ? error.message : "Erreur inconnue"}`,