Backend:
- Detect and classify 403 responses into three types:
validation (account needs Google verification),
violation (terms of service / banned),
forbidden (generic 403)
- Extract verification/appeal URLs from 403 response body
(structured JSON parsing with regex fallback)
- Add needs_verify, is_banned, needs_reauth, error_code fields
to UsageInfo (omitempty for zero impact on other platforms)
- Handle 403 in request path: classify and permanently set account error
- Save validation_url in error_message for degraded path recovery
- Enrich usage with account error on both success and degraded paths
- Add singleflight dedup for usage requests with independent context
- Differentiate cache TTL: success/403 → 3min, errors → 1min
- Return degraded UsageInfo instead of HTTP 500 on quota fetch errors
Frontend:
- Display forbidden status badges with color coding (red for banned,
amber for needs verification, gray for generic)
- Show clickable verification/appeal URL links
- Display needs_reauth and degraded error states in usage cell
- Add Antigravity tier label badge next to platform type
Tests:
- Comprehensive unit tests for classifyForbiddenType (7 cases)
- Unit tests for extractValidationURL (8 cases including unicode escapes)
- Integration test for FetchQuota forbidden path
