feat: translate API error messages to English

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/app/api/dashboard/stats/route.ts

@@ -10,7 +10,7 @@ export async function GET(request: NextRequest) {
 
     if (!session?.user) {
       return NextResponse.json(
-        { error: 'No autorizado' },
+        { error: 'Unauthorized' },
         { status: 401 }
       );
     }
@@ -315,7 +315,7 @@ export async function GET(request: NextRequest) {
   } catch (error) {
     console.error('Error fetching dashboard stats:', error);
     return NextResponse.json(
-      { error: 'Error al obtener estadísticas del dashboard' },
+      { error: 'Error fetching dashboard statistics' },
       { status: 500 }
     );
   }