feat(admin): show progressive hourly gateway usage

[chrarnoldus]

Summary

• Replace daily gateway usage queries with sequential, fixed one-hour UTC queries while preserving the current inclusive date-range and model selectors.
• Keep PostgreSQL read-replica execution, production primary-fallback protection, positive input-token filtering, user-BYOK exclusion, and the existing ten-minute timeout per query.
• Publish immutable hourly snapshots into the React Query cache as queries finish, so the table and spreadsheet copy update while later hours are running.
• Keep completed rows visible on later failures, clearly label partial results/exports, and reset previous results when restarting a range.
• Include hour_start in results and TSV; preserve exact numeric strings and keep hourly distinct-user counts separate.

Validation

• Added hourly SQL boundary/input/replica/abort coverage and sequential-runner/React Query observer coverage for incremental results, failures, and reruns.
• Tests intentionally left to CI as requested.
• Formatting and git diff --check passed. pnpm validation commands triggered dependency refresh and exceeded this container's two-minute limit; installed check tools were also invoked directly.
• UI follows the Cloud overlay and interaction-quality guidance; no unrelated design changes.

Cancellation

• Request cancellation stops further hourly scheduling and is checked before SQL starts after connection acquisition. Already-running PostgreSQL work can continue until completion or its statement timeout.

[kilo-code-bot]

Code Review Summary

Status: No Issues Found | Recommendation: Merge

Files Reviewed (5 files)

• apps/web/src/app/admin/gateway/UsageContent.tsx
• apps/web/src/app/admin/gateway/gateway-usage-report.ts
• apps/web/src/app/admin/gateway/gateway-usage-report.test.ts
• apps/web/src/routers/admin/gateway-usage-router.ts
• apps/web/src/routers/admin/gateway-usage-router.test.ts

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_{Reviewed by grok-4.6 · Input: 89.1K · Output: 18.1K · Cached: 617.6K}

_{Review guidance: REVIEW.md from base branch main}