refactor(web): remove useMixedTranslation, better resource loading (#30630)

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

web/__tests__/goto-anything/search-error-handling.test.ts

@@ -14,6 +14,14 @@ import { fetchAppList } from '@/service/apps'
 import { postMarketplace } from '@/service/base'
 import { fetchDatasets } from '@/service/datasets'
 
+// Mock react-i18next before importing modules that use it
+vi.mock('react-i18next', () => ({
+  getI18n: () => ({
+    t: (key: string) => key,
+    language: 'en',
+  }),
+}))
+
 // Mock API functions
 vi.mock('@/service/base', () => ({
   postMarketplace: vi.fn(),