Remove card/shadow layout in favor of a clean centered design.
Add tree logo, simplify inputs (placeholder-only, no labels),
use soft buttons, narrow form width, and clean up footer links.
* fix: remove unused AUTUMN_SEO_DATA_USAGE_FEATURE_ID export
This constant became unused after the billing buckets separation
in #57 which replaced it with separate balance/topup feature IDs.
* fix: resolve oxlint errors from billing buckets PR
Add eslint-disable for max-lines in HostedBillingContent.tsx.
Type trackMock properly in dataforseoClient.test.ts to eliminate
unsafe type assertions without needing eslint-disable.
