refactor: remove models snapshot feature and related code

- Remove models snapshot UI section from Models page
- Delete models API route handler and related logic
- Remove models store implementation and exports
- Clean up internationalization messages for removed feature
- Update main entry point exports to exclude models store

src/pages/Models/index.tsx

@@ -1,4 +1,3 @@
-import ModelsSection from './components/ModelsSection';
 import ProvidersSection from './components/ProvidersSection';
 import UsageHistorySection from './components/UsageHistorySection';
 import { useModelsCopy } from './copy';
@@ -21,7 +20,6 @@ export default function ModelsPage() {
         </div>
 
         <div className="min-h-0 flex-1 space-y-12 overflow-y-auto pb-10 pr-2">
-          <ModelsSection />
           <ProvidersSection />
           <UsageHistorySection />
         </div>