Refactor media upload handling in MediaPanel: remove direct upload logic and integrate useUploadStore for file enqueueing. Update translations for upload status and add UploadSnackbar component to display upload notifications in the UI.

frontend/src/shared/api/query-client.ts

@@ -0,0 +1,4 @@
+import { QueryClient } from '@tanstack/react-query'
+
+/** Единый экземпляр — доступен и провайдеру, и коду вне React (напр. фоновому загрузчику медиа). */
+export const queryClient = new QueryClient()

frontend/src/shared/lib/i18n.ts

@@ -107,6 +107,7 @@ const resources = {
           upload: 'Загрузить',
           uploaded: 'Файл загружен, идёт обработка',
           uploadedCount: 'Загружено файлов: {{count}}',
+          uploadingCount: 'Загрузка {{done}}/{{total}}',
           skippedDuplicates: 'Пропущено дубликатов: {{count}}',
           filterActive: 'Активные',
           filterAll: 'Все',
@@ -302,6 +303,7 @@ const resources = {
           upload: 'Upload',
           uploaded: 'File uploaded, processing started',
           uploadedCount: 'Uploaded files: {{count}}',
+          uploadingCount: 'Uploading {{done}}/{{total}}',
           skippedDuplicates: 'Skipped duplicates: {{count}}',
           filterActive: 'Active',
           filterAll: 'All',