fix(ui): storage size formatting, overdue queue items, and i18n fixes

- Add formatStorageSize helper in FileManagerModal to display storage
  in GB/MB instead of raw bytes
- Show "Overdue" label for queue items whose scheduled time has passed
  by more than 1 minute
- Fix missing "in" prefix for English inDays translation
- Fix swapped justNow/now translations in Italian locale
- Fix whitespace formatting for waiting key across all locales
- Add trailing newline to date.ts and date.test.ts

frontend/src/__tests__/utils/date.test.ts

@@ -434,4 +434,4 @@ describe('formatRelativeTime', () => {
     expect(formatRelativeTime('2025-06-15T11:55:00Z', 'system', t)).toBe('5 minutes ago');
     expect(formatRelativeTime('2025-06-15T12:05:00Z', 'system', t)).toBe('in 5 minutes');
   });
-});
+});