GitLab

- Simplify OpenAI rendering: always fetch /usage, prefer fetched data over
  codex snapshot (snapshot serves as loading placeholder only)
- Remove dead code: preferFetchedOpenAIUsage, isOpenAICodexSnapshotStale,
  and unreachable template branch
- Add today-stats support for key accounts (req/tokens/A/U badges)
- Use formatCompactNumber for consistent number formatting
- Add A/U badge titles for clarity
- Filter zero-value window stats in UsageProgressBar to avoid empty badges
- Update tests to match new fetched-data-first behavior