fix: TypeScript difficulty type error in SolverWidget

Author: RagaviDevX

dashboard/src/components/dashboard/SolverWidget.tsx

@@ -122,7 +122,7 @@ export function SolverWidget({ onSolved }: SolverWidgetProps) {
         id: title.toLowerCase().replace(/\s+/g, '-'),
         title,
         slug: title.toLowerCase().replace(/\s+/g, '-'),
-        difficulty: 'Medium',
+        difficulty: 'Medium' as const,
         url: '',
         description: problem,
         constraints: [],
@@ -343,4 +343,4 @@ export function SolverWidget({ onSolved }: SolverWidgetProps) {
       </div>
     </div>
   );
-}
+}