v1.6.0

Added

• Extra usage card on the main view for accounts that purchased credits
  beyond their plan quota. Reads the OAuth endpoint's extra_usage object and
  shows used vs. monthly-limit credits (US$ used / US$ limit) with a thin
  quota meter. Only appears when the feature is enabled on the account;
  otherwise it stays hidden and the layout is unchanged.

Fixed

• A 401 from the OAuth usage endpoint no longer signs you out on the first
  transient rejection. QuotaService now attempts a single forced token
  refresh and retries the request; credentials are only cleared if the refresh
  itself fails or the retry is still 401, matching the existing 403
  re-auth pattern.